DSpace Arşivi :: by Yazar "Timur, Mahir" değerine göre listeleniyor

Yazar "Timur, Mahir" seçeneğine göre listele

Listeleniyor 1 - 14 / 14

Antimicrobial, Antioxidant Activity of the Essential Oil of Bay Laurel from Hatay, Turkey
(Taylor & Francis Ltd, 2013) Yilmaz, Ebru Sebnem; Timur, Mahir; Aslim, Belma
The aim of this study was to evaluate the antimicrobial and antioxidant activity of the essential oil (EO) extracted from the leaves of Laurus nobilis L. The oil was analyzed by gas chromatography and mass spectrometry (GC-MS). Twenty seven components were identified, representing 96.6 % of the EO. The main compounds identified were 1,8-cineole (51.8 %), alpha-terpinyl acetate (11.2 %), and sabinene (10.1 %). The oil was screened for possible antioxidant activity using two complementary test systems: DPPH (2,2-diphenylpicrylhydrazyl) free radical-scavenging and the beta-carotene/linoleic acid assay. Both of these in vitro methods showed that the EO was a less powerful reducing agent than the well-known synthetic antioxidants, butylated hydroxytoluene and ascorbic acid. Also, the antimicrobial activity of the EO was tested against a panel of food-spoiling bacteria and one yeast strain. The minimum inhibitory concentration values for microorganisms that were sensitive to L. nobilis EO ranged from 125-2000 mu g/mL.
Comparison of chemical composition of the essential oil of Laurus nobilis L. leaves and fruits from different regions of Hatay, Turkey
(Triveni Enterprises, 2007) Sangun, Mustafa Kemal; Aydin, Ebru; Timur, Mahir; Karadeniz, Hatice; Caliskan, Mahmut; Ozkan, Aydin
The essential oils of the leaves and fruits from bay (Laurus nobilis L.) grown in Antakya, Yayladagi and Samandagi were isolated by solvent extraction and analysed by capillary gas chromatography (GC), gas chromatography and mass spectrometry (GC/MS). In Antakya, Yayladagi and Samandagi the chemical compositions of the fruits and leaves were similar according to qualitative and quantitative analysis. Although in both fruits and leaves the major component was found to be 1.8-Cineole a concentration of about 50% compared with essential oils. The composition of the essential oil from the leaves has high content of 1.8-Cineole, Sabinene and alpha-Terpinyl acetate, but a low content of alpha-Pinene, alpha-Phellandrene and trans-beta-osimen. 1.8-Cineole was found major component of the leaves essential oil collected from Samandagi (59.94%) which is sea coast of region. Interestingly alpha-Pinene, beta-Pinene, alpha-Phellandrene, 1.8-Cineole and trans-beta-osimen were found the major components of fruits of Laurus nobilis L. harvested from Antakya, Yayladagi and Samandagi. Trans-beta-osimen was detected as the major component of fruits essential oil collected again from Samandagi (28.35%).
Defne meyvası yağ veriminin arttırılması ve bileşiminin gaz kromatografi cihazı ile belirlenmesi
(Hatay Mustafa Kemal Üniversitesi, 2001) Timur, Mahir; Özkan, Aydın
ÖZET DEFNE MEYVASI YAĞ VERİMİNİN ARTTIRILMASI VE BİLEŞİMİNİN GAZ KROMATOGRAFİ CİHAZI İLE BELİRLENMESİ Defne Hatay bölgesinde önemli pazar potansiyeline sahip doğal yetişen bir bitkidir. Türkiye dünya defne yaprağı pazarında % 90'ın üzerinde bir pay ile en önemli üretici ülkedir. Defne meyvalarından elde edilen defneyağı Ortadoğu ülkelerine ihraç edilmekte veya sabun üretiminde kullanılmaktadır. Defneyağı, defne meyvalarının ilkel yöntemler kullanılarak suda kaynatılması ile elde edilmektedir. Meyvadaki ortalama yağ oranı %20 iken bu yöntemle yaklaşık % 1 0 yağ elde edilmekte ve bu esnada meyvada %1 -4 oranında bulunan eterik yağlar büyük oranda yok olmaktadır. Bu çalışmada Hatay bölgesinin değişik yörelerinden toplanan defne meyvası örneklerinde çözücü ekstraksiyonu, soxhlet ekstraksiyonu, kaynatma yöntemleri uygulanarak ekstraksiyon yönteminin ve süresinin verime etkisi incelenmiştir. Daha kısa sürede daha yüksek verime ulaşabilmek amacıyla ortama eklenen enzim ve iyon değiştirici katkılarının verime etkisi saptanmıştır. Elde edilen defneyağı örnekleri sabunlaştırılıp BF3- Metanol yöntemi ile metil esterlerlerine dönüştürüldükten sonra GC-MS analizleri yapılarak değişik yıllarda, değişik yörelerden elde edilen defneyağı örneklerinin yağ asidi bileşimleri belirlenmiştir. 2001, 113 sayfa
Electrochemical synthesis and characterization of polypyrrole/chitosan composite on platinum electrode: Its electrochemical and thermal behaviors
(Elsevier Sci Ltd, 2010) Yalcinkaya, Sueleyman; Demetgul, Cahit; Timur, Mahir; Colak, Nureddin
The electrochemical polymerization of conducting polymers is a simple and most convenient method for preparation of a film on the metal surface. The polypyrrole/chitosan composite film has been electrochemically synthesized on platinum electrode by using cyclic voltammetry (CV) technique. The synthesis solution was prepared by dissolving of pyrrole and chitosan in aqueous oxalic acid solution. The characterization of this film was done using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermal analysis (TG-DTA) techniques. The synthesized composite film was different in aspect of morphology when compared to chitosan and polypyrrole. The TG-DTA results revealed that the composite film had better thermal stability with respect to chitosan. The electrochemical measurement has shown that the composite film is very stable and electroactive. (C) 2009 Elsevier Ltd. All rights reserved.
Electropolymerization of CuII-(N,N?-bis(3-methoxysalicylidene)-2-aminobenzylamine) on platinum electrode: Application to the electrocatalytic reduction of hydrogen peroxide
(Elsevier Science Sa, 2011) Deletioglu, Didem; Yalcinkaya, Suleyman; Demetgul, Cahit; Timur, Mahir; Serin, Selahattin
The complex of copper (II) with N,N'-bis(3-methoxysalicylidene)-2-aminobenzylamine (H2L) was synthesized and characterized by elemental analysis, magnetic susceptibility, UV-vis. and FT-IR spectroscopy. The results showed that the tetradentate ligand coordinated to the Cu(II) ion through the azomethine nitrogen and phenolic oxygen atoms. The prepared complex [CuL] was electropolymerized on platinum electrode surface in a 0.1 mol dm(-3) solution of lithium perchlorate in acetonitrile by cyclic voltammetry between 0 and 1.6V vs. Ag/Ag+. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), conductance measurements, FT-IR and SEM were used to characterize polymer film of Cu(II) complex. The reduction of hydrogen peroxide on poly[CuL] has been investigated mainly in phosphate buffer medium (pH 7.2), between 0 and -0.8 V versus Ag/Ag+ at a scan rate 0.1 V s(-1). (c) 2011 Elsevier B.V. All rights reserved.
Essential Oil and Fatty Acid Composition and Antioxidant Capacity and Total Phenolic Content of Parsley Seeds (Petroselinum crispum) Grown in Hatay Region
(Assoc Pharmaceutical Teachers India, 2017) Mert, Ahmet; Timur, Mahir
The aim of the present study was to investigate the essential oil and fatty acid compositions and antioxidant capacity and total phenolic content of parsley seeds grown in Arsuz/hatay region. Parsley seeds had a moisture content of 12,6 Qwt.% and ash content of 6,86 wt.% while the essential oil content of 2,52 wt.% and total lipid content of 8,85 wt.%. The essential oil was analyzed by gas chromatography and thirty two volatile compounds were determined. The composition of fatty acids were also investigated by GC and seven content were determined. The seeds were extracted with methanol for determination of antioxidant capacity and total phenolic content. Total phenol concentration was found 67.25 +/- 5.9mg gallic acid equivalent/g of extract powder. DPPH free radical-scavenging activity IC50 was found as 0,523 +/- 12 mg/ml. From the Trolox calibration curve cupric reducing antioxidant capacity TEACCUPRAC: 17,95 mu g / mL was found. Results were compared with standard antioxidant compound BHA and BHT.
Hatay bölgesinde üretilen firiğin besinsel değerlerinin incelenmesi
(2017) Carşanba, Erdem; Akça, İsmail; Timur, Mahir
Bu çalışmada, Hatay bölgesinde üretilen Firiğin besin değeri, dört Firik numunesi kullanılarak incelenmiştir. Firik örneklerinin protein, kül, nem, toplam şeker, yağ, tuz, ham selüloz içerikleri ve yağ asidi profili belirlenerek elde edilen değerler bulgur ve pirinç gibi benzer gıdalar ile karşılaştırılmıştır. Firiğin, protein ve kül içeriği bulgur ve pirinçten yüksek, şeker ve yağ içeriği ise daha düşüktür. Buna ek olarak, esansiyel yağ asitleri olarak bilinen yüksek miktarda linoleik asit ve oldukça uygun miktarda linolenik asit elde edilmiştir. Sonuç olarak, Hatay'da üretilen Firiğin karbonhidrat esaslı diğer gıdalardan daha iyi besinsel özelliklere sahiptir. Elde edilen veriler Firi k günlük diyetin besin değerini artırmak için kullanılabileceğini göstermektedir
Synthesis and characterization of a Schiff base derived from 2-aminobenzylamine and its Cu(II) complex: electropolymerization of the complex on a platinum electrode
(Taylor & Francis Ltd, 2010) Demetgul, Cahit; Deletioglu, Didem; Karaca, Filiz; Yalcinkaya, Sueleyman; Timur, Mahir; Serin, Selahattin
A precursor (H3A) was synthesized by the mono condensation of 2-aminobenzylamine with salicylaldehyde and then a tetradentade Schiff-base ligand (H2L) prepared by using H3A and 3-methoxysalicylaldehyde. The copper(II) complex of this new ligand was prepared and characterized by elemental analysis, electronic absorption, Fourier transform infrared (FT-IR), and magnetic susceptibility. For the ligand, 1H- and 13C-NMR and liquid chromatography mass spectrometry (LC-MS) spectra were obtained. The tetradentate ligand is coordinated to Cu(II) through the phenolic oxygen and azomethine nitrogen. The use of this metal complex in the preparation of a modified electrode is also described. CuL was electropolymerized on a platinum electrode surface in a 0.1 mol dm-3 solution of lithium perchlorate in acetonitrile by cyclic voltammetry between 0 and 1.6 V versus Ag/Ag+. Electrochemical properties of the electroactive polymeric film have been investigated and a surface confined polymerization mechanism was proposed.
Synthesis and Metal Ion Uptake Studies of Silica Gel-Immobilized Schiff Base Derivatives and Catalytic Behaviors of their Cu(II) Complexes
(Jihad Daneshgahi, 2017) Timur, Mahir; Demetgul, Cahit
New silica supported Schiff base ligands were prepared by the condensation reaction of 4,6-diacetylresorcinol with silica-gel derivatives, which modified with 3-aminopropyltriethoxysilane and N-(2-aminoethyl) -3-aminopropyltrimethoxysilane. Metal ion uptake capacities of these compounds were studied towards of selected transition metal (Cd(II), Cu(II), Co(II), Mn(II), Pb(II) and Ni(II)) cations in an aqueous medium. In addition, Cu(II) complexes of these ligands were prepared by using heterogeneous reaction conditions. The synthesized compounds were characterized by using elemental analysis, FT-IR, DR-UV-vis., CP/MAS C-13-NMR, AAS, XRD and TGA techniques. Moreover, the morphological and chemical properties of these compounds were investigated by using a scanning electron microscope (SEM) coupled to an energy-dispersive X-ray spectrometer (EDX). The catalytic performances of the Cu(II) complexes were investigated on H2O2 decomposition. These complexes displayed good catalytic activities towards the decomposition of H2O2 as heterogeneous catalysts.
Synthesis and metal ion uptake studies of silica gel-immobilized schiff base derivatives and catalytic behaviors of their Cu(II) complexes
(Jihad Danishgahi, 2017) Timur, Mahir; Demetgül, Cahit
New silica supported Schiff base ligands were prepared by the condensation reaction of 4,6-diacetylresorcinol with silica-gel derivatives, which modified with 3- aminopropyltriethoxysilane and N-(2-aminoethyl) -3-aminopropyltrimethoxysilane. Metal ion uptake capacities of these compounds were studied towards of selected transition metal (Cd(II), Cu(II), Co(II), Mn(II), Pb(II) and Ni(II)) cations in an aqueous medium. In addition, Cu(II) complexes of these ligands were prepared by using heterogeneous reaction conditions. The synthesized compounds were characterized by using elemental analysis, FT-IR, DR-UV-vis., CP/MAS13C-NMR, AAS, XRD and TGA techniques. Moreover, the morphological and chemical properties of these compounds were investigated by using a scanning electron microscope (SEM) coupled to an energy-dispersive X-ray spectrometer (EDX). The catalytic performances of the Cu(II) complexes were investigated on H2O2 decomposition. These complexes displayed good catalytic activities towards the decomposition of H2O2 as heterogeneous catalysts. © 2017, Jihad Danishgahi. All rights reserved.
Synthesis and swelling peculiarities of new hydrogels based on the macromolecular reaction of anhydride copolymers with -aminopropyltriethoxysilane
(Taylor & Francis Ltd, 2016) Timur, Mahir; Can, Hatice Kaplan
This work describes the synthesis and macromolecular reactions of maleic anhydride (MA)-acrylamide (AAm) binary and MA-vinyl acetate (VA)- AAm ternary reactive copolymers with -aminopropyltriethoxysilane (APTS) as a polyfunctional crosslinker. Swelling parameters such as the start-time of the hydrogel-formation, initial rate of swelling, swelling rate constant, equilibrium swelling, and equilibrium water content (EWC) are determined for polymers/APTS/water systems with certain copolymer/crosslinker ratios (1.4/1 and 9/1). The formation of a hyperbranched network structure by the fragmentation of the side-chain reactive groups in the systems studied has also been confirmed by the Fourier Transform Infrared (FTIR) method.
Synthesis of Schiff base-containing benzoxazine derivatives
(Wiley, 2019) Timur, Mahir; Nur, Yusuf; Sikar, Huseyin
The excellent chemical and physical properties of benzoxazine resins and the functionality of Schiff bases were combined in one compound's structure, creating newly designed benzoxazine derivatives that can form complexes with metals. The new type of benzoxazine monomer was synthesized via the ring-closure reaction of formaldehyde, aniline, and three newly designed Schiff bases. The presence of the Schiff base in the molecular structure of these novel benzoxazine monomers enables them to trap metals as the functional compounds, like Cu, from a solution. Thermally initiated polymerization occurs at a lower temperature by the formation of intermolecular and intramolecular hydrogen bonds between imine, oxazine, Schiff base hydroxyl groups, and the newly generated hydroxyl groups. The thermal behavior of the bisbenzoxazine monomers was investigated with Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry, and then they were cured at 120, 180, and 230 degrees C. According to the magnetic susceptibility, FTIR, scanning electron microscopy with energy dispersive X-ray spectroscopy, TGA, and microwave plasma atomic emission spectroscopy results, it is shown that Cu(II) complexes of the compounds were also succesfully synthesized, and they proved to be successful in catching metal. This is due to the functionality of Schiff bases forming the metal complexation in the compounds. The poly(bisbenzoxazine)s also showed high limiting oxygen index (31-37), low ring-opening temperature (150-190 degrees C), high char yield (35%-49%), and excellent thermal stability, due to the highly crosslinked nature of the polymers. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47908.
Synthesis, characterization, swelling behavior and metal uptake studies of dichloroglyoxime crosslinked chitosan derivative
(Hitit Üniversitesi, 2019) Timur, Mahir
New crosslinked derivative of chitosan was prepared by the condensation reaction of chitosan (CS) and dichloro glyoxime. Structural analysis of chitosan derivative (CSL) was performed by elemental analysis (C, H, N), SEM measurements, FT-IR, solid-state 13C CP/MAS NMR, XRD-powder and TGA. Crosslinking ratio was determined from the elemental analysis by using the C/N and found to be 70%. The swelling behavior of derivative was investigated on pH 3-7 and 10 at 25 and 37°C. Metal ion uptake capacity was studied towards of selected transition metals Cu(II), Ni(II), Co(II), Fe(II) and (Cd(II) cations in aqueous medium. According to the results of the analyses; water retention capacity and metal uptake capacity of new cross-linked chitosan derivative is higher than chitosan and metal uptake sequence are Cu(II) > Fe(II) >Cd(II) > Co(II) > Ni(II) respectively.
Synthesis, Characterization, Swelling, and Metal Uptake Studies of Aryl Cross-Linked Chitosan Hydrogels
(Amer Chemical Soc, 2018) Timur, Mahir; Pasa, Ahmet
Today, many chemical modifications are being made to increase the utilization of chitosan and to make the best use of it. In this study, four novel cross-linked chitosan derivatives in the form of hydrogel (CS-L1 CS-L2, CS-L3, and CS-L4) were prepared by the condensation of chitosan with anisole-based phenolic and nonphenolic aromatic dicarbonyls. Structural analyses were performed by elemental analysis (C, H, N), scanning electron microscopy, Fourier transform infrared, C-13-CP/MAS (cross-polarization, magic angle spinning) nuclear magnetic resonance, powder X-ray diffraction, and thermogravimetric analysis techniques. Metal ion uptake capacities were studied for selected transitionmetal cations in aqueous medium. The amount of metal ions was determined by microwave plasma-atomic emission spectroscopy. In addition, the swelling behaviors were investigated at different temperatures (25 and 37 degrees C) and at different pH values (3, 7, and 10). The order of the selectivity of cross-linked chitosan derivatives toward metal ions was found to be Cu(II) > Cd(II) > Fe(II) > Co(II) > Ni(II). The results showed that the derivatives exhibited the property of hydrogel and suggest that they could be applied in many areas such as metal removing, water removing, and biological applications.

Yazar "Timur, Mahir" seçeneğine göre listele

Sayfa Başına Sonuç

Sıralama seçenekleri