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Articles 1 - 30 of 62
Full-Text Articles in Physical Sciences and Mathematics
Evidence For A Hybrid Ping Pong-Semirandom Mechanism For Human Jejunal Glutathione Disulfide Reductase, Nazmi̇ Özer, İzzet Hamdi̇ Öğüş
Evidence For A Hybrid Ping Pong-Semirandom Mechanism For Human Jejunal Glutathione Disulfide Reductase, Nazmi̇ Özer, İzzet Hamdi̇ Öğüş
Turkish Journal of Chemistry
Initial rate versus substrate concentration, [S], profiles (at pH 7.4, 37^oC) for human jejunal glutathione disulfide reductase indicated partial substrate inhibition by GSSG at fixed [NADPH] \le 40 \mu M. Saturation by NADPH assumed an increasingly sigmoidal character at fixed [GSSG] \ge 20 \mu M. The results were interpreted in terms of a hybrid ping pong-semirandom mechanism proceeding through both E.NADPH (ping pong pathway) and E.GSSG (ordered pathway) complexes. When V(apparent) versus [GSSG] and [NADPH] were plotted, hyperbolic curves were obtained. Plotting 1/Vm(apparent) versus 1/[NADPH] and 1/[GSSG] yielded two lines with different slopes but intersecting at the same point on …
Photocuring Of Acrylate Oligomers In The Presence Of Vinyl Phosphonic Acids As A Flame Retarding Monomer And The Properties Of The Cured Films, Tüli̇n İmamoğlu, Yusuf Yağci
Photocuring Of Acrylate Oligomers In The Presence Of Vinyl Phosphonic Acids As A Flame Retarding Monomer And The Properties Of The Cured Films, Tüli̇n İmamoğlu, Yusuf Yağci
Turkish Journal of Chemistry
Photocuring of formulations containing polyurethane based acrylates and a flame retarding monomer (FR), namely vinyl phosphonic acid with an \alpha -cleavage type photoinitiator; 2-hydroxy-2-methylphenyl propane-1-one were studied. The flame retardancy, and the physical and mechanical properties of the cured films were determined.
Determination Of Hydrochlorothiazide And Enalapril Maleate In Tablet Formulations By Reversed-Phase Hplc, Idrees F. Al-Momani̇
Determination Of Hydrochlorothiazide And Enalapril Maleate In Tablet Formulations By Reversed-Phase Hplc, Idrees F. Al-Momani̇
Turkish Journal of Chemistry
A high-performance liquid chromatographic procedure is presented for the determination of hydrochlorothiazide (HCT) and enalapril maleate (EM) in pharmaceutical tablets. An aliquot of the sample is dissolved in 15% acetonitrile (ACN) containing thiophylline as an internal standard and chromatographed on a Supelcosil LC-8 (5 \mu m), (150 mm x 4.6 mm i.d.) column. The mobile phase was 3.0 mM tetrabutylammoniumhydrogen sulfate (TBAHS) in ACN/water/triethylamine (TEA), (14, 85.6, 6.4 V/V) adjusted to pH 4.1 by glacial acetic acid. The detection was at 220 nm. The method was tested for linearity, accuracy, recovery, and specificity.
The Composition Of Essential Oils From Two Varieties Of Sideritis Erythrantha Var. Erythrantha And Var. Cedretorum, Nurhayat Tabanca, Neş'E Kirimer, K. Hüsnü Can Başer
The Composition Of Essential Oils From Two Varieties Of Sideritis Erythrantha Var. Erythrantha And Var. Cedretorum, Nurhayat Tabanca, Neş'E Kirimer, K. Hüsnü Can Başer
Turkish Journal of Chemistry
Water distilled essential oils from two varieties of Sideritis erythrantha: var. erythrantha} and var. cedretorum, both endemic in Turkey, were analysed by GC/MS. The main components were characterized as \alpha -pinene (16.3-19.5%) and sabinene (6.1- 10.4%) for var. erythrantha; myrcene (21.9-24.3%) and \alpha -pinene (11.4- 12.4%) for var. cedretorum.
Investigation Of The Microporous And Mesoporous Structures Of The Reşadiye (Tokat/Turkey) Bentonite And Its Fractions, Müşerref Önal, Yüksel Sarikaya, Tülay Alemdaroğlu
Investigation Of The Microporous And Mesoporous Structures Of The Reşadiye (Tokat/Turkey) Bentonite And Its Fractions, Müşerref Önal, Yüksel Sarikaya, Tülay Alemdaroğlu
Turkish Journal of Chemistry
It was determined by X-ray diffraction that, besides containing clay minerals such as montmorillonite and illite, the original bentonite contained also clinoptilolite, opal-C, quartz, calcite and dolomite. The original bentonite was separated into four fractions by decantation and precipitation from its aqueous suspension. The adsorption and desorption of nitrogen on the original bentonite and its fractions at 77 K were investigated. The specific surface areas of the samples were determined according to the methods of Brunauer-Emmett-Teller, de Boer-Lippens, and Harkins-Jura by using the adsorption data. The mesopore size distribution curves were plotted by using the desorption data. The specific micropore …
Towards The Asymmetric Synthesis Of Ascochlorin, Özdemi̇r Doğan, Wolfgang Oppolzer
Towards The Asymmetric Synthesis Of Ascochlorin, Özdemi̇r Doğan, Wolfgang Oppolzer
Turkish Journal of Chemistry
A synthetic approach is described to the asymmetric synthesis of ascochlorin (1), an antiviral antibiotic, based on the construction of a sesquiterpene unit via asymmetric Diels-Alder reaction of tigloyl sultam 4 & butadiene, and the introduction of the aromatic side chain (C9-C12 unit) by employing cuprate chemistry.
Determination Of Some Of The Physicochemical Properties Of Fine Alumina Powders Prepared By Emulsion Evaporation, Yüksel Sarikaya, İsmet Sevi̇nç, Müşerref Önal, Tülay Alemdaroğlu
Determination Of Some Of The Physicochemical Properties Of Fine Alumina Powders Prepared By Emulsion Evaporation, Yüksel Sarikaya, İsmet Sevi̇nç, Müşerref Önal, Tülay Alemdaroğlu
Turkish Journal of Chemistry
In order to prepare fine alumina powders, an emulsion was prepared under optimum conditions. The emulsion was examined by optical microscopy and the prepared fine alumina powders were characterised by electron microscopy. The particles were formed of porous spheres and their sizes were between 1 and 10 \\mum. The powder samples were sintered by varying the temperature between 700 and 1600°C. The adsorption and desorption of nitrogen on these samples were investigated. By using the adsorption data, the specific surface areas were calculated according to different procedures and the correlation between them was discussed. The specific micropore and mesopore volumes …
Adsorption Of Non-Ionic Surface Active Agent On Fine Coal And Lignite, Zeki̇ Aktaş
Adsorption Of Non-Ionic Surface Active Agent On Fine Coal And Lignite, Zeki̇ Aktaş
Turkish Journal of Chemistry
The adsorption of Triton X-100 in aqueous solution on the less than 53 \\mum size fractions of Tunçbilek lignite and Zonguldak bituminous coal was studied. The adsorption isotherms were formed for 5, 30 and 1,440 (equilibrium) minutes. The isotherms were evaluated using both Langmuir and Freundlich adsorption equations. Concentrations of the reagent in the monolayer after equilibrium adsorption were determined to be 8.17 and 7.27 \\muM/g coal for the lignite and bituminous coal using the Langmuir adsorption equation. The specific adsorption capacity per unit area of Zonguldak bituminous coal was 5.3 times higher than that of Tunçbilek lignite. The adsorption …
Evaluation Of Sample Pre-Treatment Procedures For The Determination Of Cr, Ni And V In Biological Matrices By Etaas, Jan Medved, Jana Kubova, Eva Chmielewska, Vladimir Stresko
Evaluation Of Sample Pre-Treatment Procedures For The Determination Of Cr, Ni And V In Biological Matrices By Etaas, Jan Medved, Jana Kubova, Eva Chmielewska, Vladimir Stresko
Turkish Journal of Chemistry
Electrothermal atomic absorption spectrometry (ETAAS) was applied for the determination of chromium, nickel and vanadium in biological materials (earthworms, feather, lucerne). Three different decomposition procedures of biological matrices are presented. The utilization of NH_4H_2PO_4, Mg(NO_3)_2 and Pd(NO_3)_2+ Mg(NO_3)_2 as chemical modifiers are investigated and compared. Optimal temperature conditions for the electrothermal determination of Cr, Ni and V are selected. Precision of the determination expressed as relative standard deviations for Cr, Ni and V varied from 6 to 22% . The detection limits are for Cr 8 \\mu g kg^{ - 1}, Ni 12 \\mu g kg^{ - 1}, and V …
Selenium Speciation In Karakaya Dam Lake's Water (Malatya-Turkey), F. Zehra Küçükbay, Mustafa Demi̇r
Selenium Speciation In Karakaya Dam Lake's Water (Malatya-Turkey), F. Zehra Küçükbay, Mustafa Demi̇r
Turkish Journal of Chemistry
Concentrations of total inorganic selenium, Se(IV), Se(VI) and organically bonded selenium from samples of Karakaya dam lake\\\'s water were determined using ammonium pyrollidine dithio carbamate (APDC) as a chelating agent and subsequent adsorption on amberlite type XAD-8 resins. Eluted analytes are taken up in a matrix free acidic solution suitable for graphite furnace atomic absorption spectroscopy (GFAAS). According to our results, levels of the total inorganic selenium, Se(IV), Se(VI) and organically bonded selenium were found to be between 0.11 \\pm 0.01 and 0.17 \\pm 0.01 \\mug/L, 0.07 \\pm 0.01 and 0.12 \\pm 0.01 \\mug/L, 0.02 \\pm 0.01 and 0.05 \\pm …
Calculation Of Multi-Center Integrals For The Region Of Moderate And Weak Overlap, Abdulhali̇k Karabulut, Gökhan Budak, Lütfü Demi̇r, Nagi̇f Sefteroğlu Nabi̇yev, Yusuf Şahi̇n
Calculation Of Multi-Center Integrals For The Region Of Moderate And Weak Overlap, Abdulhali̇k Karabulut, Gökhan Budak, Lütfü Demi̇r, Nagi̇f Sefteroğlu Nabi̇yev, Yusuf Şahi̇n
Turkish Journal of Chemistry
In this study a general formula was established for multi-center integrals over Gaussian basis sets using the two-center expansion of nuclear attraction and electron repulsion potentials. The terms of the formula are the analytical functions of interatomic distances. Three kinds of integrals contained in these formulae can be evaluated analytically. In the presented method, unlike many other popular methods, the numerical integrations procedure is unnecessary since it does not contain the incomplete gamma function. A computer program was written and tested for various orbitals. The calculations show that the series converge very rapidly.
Conductimetric And Potentiometric Titration Of Some Hydroxylated Cinnamic Acids With Tetrabutylammonium Hydroxide In Non-Aqueous Media, A.Hakan Aktaş, Gülsüm Yaşar, Güleren Özkan Alsancak, Şahi̇nde Demi̇rci̇
Conductimetric And Potentiometric Titration Of Some Hydroxylated Cinnamic Acids With Tetrabutylammonium Hydroxide In Non-Aqueous Media, A.Hakan Aktaş, Gülsüm Yaşar, Güleren Özkan Alsancak, Şahi̇nde Demi̇rci̇
Turkish Journal of Chemistry
In this study, four hydroxycinnamic acids, namely 3,4-dihydroxycinnamic acid, 4-hydroxycinnamic acid, 4-hydroxy --3- methoxycinnamic acid and 4-hydroxy-3,5-dimethoxycinnamic acid, were titrated conductimetrically and potentiometrically using triethylamine and tetrabutylammonium hydroxide in acetonitrile, 2-propanol, and pyridine solvents under a nitrogen atmosphere at 25 ^oC. In conductimetric titration with tetrabutylammonium hydroxide all of the compounds exhibited conventional stoichiometric titration curves in 2-propanol . As is evident from the titration curves, all these compounds gave two well-defined end points. The first end point corresponds to exactly one equivalent and the second one to the two equivalents of the base. In conductimetric titration with tetrabutylammonium hydroxide, …
Structural Studies Of Water-Soluble \Beta-Brominated Manganese Porphyrins: Stabilities Of Mntdcsppbr _{8} And Mntsppbr _{8} As Homogeneous And Supported Reagents Toward Hydrogen Peroxide And Sodium Hypochlorite, Hayretti̇n Türk, Hüseyi̇n Berber
Structural Studies Of Water-Soluble \Beta-Brominated Manganese Porphyrins: Stabilities Of Mntdcsppbr _{8} And Mntsppbr _{8} As Homogeneous And Supported Reagents Toward Hydrogen Peroxide And Sodium Hypochlorite, Hayretti̇n Türk, Hüseyi̇n Berber
Turkish Journal of Chemistry
This article describes the structural stabilities of [2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(2,6-dichloro-3-sulfonatophenyl)porphinato]manganese(III) X (where X = H_{2}O and/or OH^{-} , depending on pH) (MnTDCSPPBr_{8} ) and [2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetra(4-sulfonatophenyl)porphinato] manganese(III) X (where X = H_{2}O and/or OH^{-} , depending on pH) (MnTSPPBr_{8} ) toward H_{2}O_{2} and NaOCl at various pH's, I = 0.2 M and 30^oC. In addition, the structural stabilities of these manganese porphyrins were investigated when they were bound to quaternary ammonium containing supports, namely, hexadecyltrimethylammonium bromide (CTAB), 2,6-ionene, 2,10-ionene and a poly[(vinylbenzyl)trimethylammonium chloride] latex. In alkaline media, both manganese porphyrins degraded and precipitated even in the absence of both of the oxidants. In …
Determination Of The Thermodynamic Properties Of Poly [2-(3-Phenyl-3-Methylcyclobutyl)-2-Hydroxyethyl Methacrylate-Co-Methacrylic Acid] At Infinite Dilution By Inverse Gas Chromatography, İsmet Kaya, Kadi̇r Demi̇relli̇
Determination Of The Thermodynamic Properties Of Poly [2-(3-Phenyl-3-Methylcyclobutyl)-2-Hydroxyethyl Methacrylate-Co-Methacrylic Acid] At Infinite Dilution By Inverse Gas Chromatography, İsmet Kaya, Kadi̇r Demi̇relli̇
Turkish Journal of Chemistry
Some thermodynamic quantities were obtained for the interactions of poly [2-(3-phenyl -3- methylcyclobutyl)-2-hydroxyethyl methacrylate-co-methacrylic acid] Poly (PCHEMA-co-MA) with alcohols, ketones, acetates, aromatics and n-alkanes by inverse gas chromatography in the temperature range of 150-180^oC. The specific retention volumes, Vg^o, weight fraction activity coefficients of solute probes at infinite dilution, \Omega_{1}^{\infty} and Flory-Huggins thermodynamic interaction parameters, \chi_{12}^{\infty} between polymers and solvents were determined. The partial molar free energy, \DeltaG_{1}^{\infty} , the partial molar heat of mixing, \DeltaH_{1}^{\infty} , at infinite dilution and the solubility parameters of the polymer, \delta_{2} , were calculated. The copolymer was characterized by ^1 H-NMR, FT-IR and …
Electrorheological Properties Of Suspensions Prepared From Polystyrene- Block- Polyisoprene Copolymer, Hali̇l İbrahi̇m Ünal, Yilmaz Yildirir, Mustafa Yavuz
Electrorheological Properties Of Suspensions Prepared From Polystyrene- Block- Polyisoprene Copolymer, Hali̇l İbrahi̇m Ünal, Yilmaz Yildirir, Mustafa Yavuz
Turkish Journal of Chemistry
Considerable scientific and industrial interest is currently being focused on a class of materials known as electrorheological (ER) fluids, which display remarkable rheological behaviour, being able to convert rapidly and repeatedly from a liquid to solid when an electric field (E) is applied or removed. In this article, the synthesis, characterization, partial hydrolysis and ER properties of polystyrene- block}-polyisoprene copolymer (COP) were investigated. The block copolymer was characterized by GPC, viscosity measurements, ^1 H-NMR and FTIR spectroscopies, particle size measurements, and elemental analysis. The polystyrene block of the copolymer was partially hydrolyzed by a series of chemical reactions and then …
Voltammetric And Polarographic Studies Of Eriochrome Black T - Nickel(Ii) Complex, Osman Çakir, Emi̇ne Ertürk Coşkun, Ender Bi̇çer, Semi̇ha Çakir
Voltammetric And Polarographic Studies Of Eriochrome Black T - Nickel(Ii) Complex, Osman Çakir, Emi̇ne Ertürk Coşkun, Ender Bi̇çer, Semi̇ha Çakir
Turkish Journal of Chemistry
The electrochemical behaviour of complexes of Eriochrome Black T (EBT) with Ni(II) was studied. It was observed that EBT forms 1:1 and 1:2 complexes with Ni(II) in 0.1 M phosphate buffer at pH 6.0 by using Square-wave voltammetry (SWV), Cyclic voltammetry (CV), Direct Current Polarography (Sampled DCP) and Controlled Potential Coulometry (CPC). It was found that the reduction processes of Ni(II)-EBT complexes are irreversible. The stability constants of the Ni(II)-EBT complexes were evaluated with the DeFord-Hume procedure at different ligand concentrations using SWV. The logarithm values of stability constants of 1:1 and 1:2 Ni(II)-EBT complexes are 8.17 and 11.17, respectively.
The Sorption Of Metals On The Polysulfone Cation Exchange Membranes, Mustafa Ersöz, İlkay Hi̇lal Güğül, Aysel Çi̇men, Betül Leylek, Sali̇h Yildiz
The Sorption Of Metals On The Polysulfone Cation Exchange Membranes, Mustafa Ersöz, İlkay Hi̇lal Güğül, Aysel Çi̇men, Betül Leylek, Sali̇h Yildiz
Turkish Journal of Chemistry
The sorption of NaCl and CaCl_2 and monovalent-divalent cation salt mixtures on the polysulfone and polysulfone with polyester support cation exchange membranes were investigated. The sorption of monovalent-divalent cation salt mixtures in contact with NaCl+CaCl_2 salt mixtures were studied at a total concentration of 0.05 M. The obtained results for polysulfone type membranes were compared with Neosepta CL-25T and CM2 cation exchange membranes.
A Comparative Study On The Recovery Of Ecori Endonuclease From Two Different Genetically Modified Strains Of Escherichia Coli, Candan Tamerler, Zeynep İlsen Önsan, Betül Kirdar
A Comparative Study On The Recovery Of Ecori Endonuclease From Two Different Genetically Modified Strains Of Escherichia Coli, Candan Tamerler, Zeynep İlsen Önsan, Betül Kirdar
Turkish Journal of Chemistry
A laboratory scale procedure developed for the purification of EcoRI restriction endonuclease was applied to two different Escherichia coli} strains, E. coli 294 and E. coli M5248, which are genetically modified to overproduce the enzyme. The purification method consisted of three successive chromatographic steps including phosphocellulose and hydroxyapatite columns and further fractionation in a second phosphocellulose column. It was shown that the second phosphocellulose separation can be omitted in the case of E. coli 294. Quality control tests indicated enzyme preparations free of contaminants and endo- or exo-nucleases. The yields obtained at the final stage of the purification were 1.3x10^{5} …
Studies On The Thermal Decomposition Of Copper (Ii) Flouride Complexes With Various Amino Acids In Nitrogen Atmosphere, Muhammad Arif, Saeed-Ur Rehman, Muhammad Arshad, Khalid Masud, Nasima Arshad
Studies On The Thermal Decomposition Of Copper (Ii) Flouride Complexes With Various Amino Acids In Nitrogen Atmosphere, Muhammad Arif, Saeed-Ur Rehman, Muhammad Arshad, Khalid Masud, Nasima Arshad
Turkish Journal of Chemistry
Thermal decomposition reactions of various copper (II) fluoride complexes of the general type Cu (L) F.xH_2O (L= asparagine(asp), arginine (arg), methionine (meth) and proline (pro), x = 3 to 4) have been studied in nitrogen atmosphere using TG and DTA techniques. A possible mechanism of decomposition is suggested on the basis of the reactions of their pyrolysis. The residues obtained at the end of various decomposition processes were identified through IR spectrometry. The kinetic parameters such as energy of activation (E^o ) and order of reaction (n) were also determined.
Fluorimetric Detection Of Insulin In The Presence Of Eu(Iii) - {Pyridine - 2,6 - Dicarboxylate} Tris Complex, Elmas Gök, Serdar Ateş
Fluorimetric Detection Of Insulin In The Presence Of Eu(Iii) - {Pyridine - 2,6 - Dicarboxylate} Tris Complex, Elmas Gök, Serdar Ateş
Turkish Journal of Chemistry
Bovine insulin solutions (pH=9.3) have maximum absorption at 278 \pm 2 nm and an intrinsic emission at 305 nm when excited at 282 nm. The relative fluorescence intensities show linear dependence on its concentration: 10 \mug/mL< [Ins] < 200 \mug/mL. When Eu(PDA)_{3}^{3-} tris complex is added to these solutions, it has a hyperchromic effect at 278 nm absorption band of insulin, sensitizing the emission intensities of central Eu^{3+} metal ion of the complex at 590 and 615 nm, and simultaneously quenching the emission intensity of hormone at 305 nm. Stern-Volmer plots show that a mechanism of bimolecular quenching at 305 nm and sensitization at 615 nm are valid up to a mole ratio, R = [Eu(PDA)_{3}^{3-}]/[Ins] < 2.0. An intramolecular rather than an intermolecular energy transfer is proposed. An apparent binding constant, log K_{app}=4.70 \pm 0.13, is calculated for Ins-[Eu(PDA)_{3}^{3-}]_{2} type product, the presence of which may offer a new luminescence technique as a diagnostic tool and an alternative to radio-iodinated (^{131}I -) insulin. A simple, rapid and accurate quantitation of insulin is proposed by using a fixed concentration of Eu(PDA)_{3}^{3-}, and measuring its initial F_{0} at \lambda_{exc}/ \lambda_{em}=282/615 nm and the difference, \DeltaF after sensitization when \sim 100 microliters of insulin sample is added. The coefficient of variation (CV), the relative error and minimum detectable amount of bovine insulin hormone are found to be 3.0%, 1.2% and 7.3 \pm 0.2 \mug /mL respectively.
The Isolation Of Carboxylic Acids From The Flowers Of Delphinium Formosum, Nedi̇me Dürüst, Seçki̇n Özden, Esra Umur, Yaşar Dürüst, Mustafa Küçüki̇slamoğlu
The Isolation Of Carboxylic Acids From The Flowers Of Delphinium Formosum, Nedi̇me Dürüst, Seçki̇n Özden, Esra Umur, Yaşar Dürüst, Mustafa Küçüki̇slamoğlu
Turkish Journal of Chemistry
From the flowers of Delphinium formosum Boiss. et Huet. (Ranunculaceae) trans-aconitic, p-hydroxybenzoic, p-coumaric, caffeic and chlorogenic acids were isolated and identified. In addition, protocatechuic, vanillic and gentisic acids were identified.
Spectrophotometric Determination Of Cobalt, Nickel Palladium, Copper, Ruthenium And Molybdenum Using Sodium Isoamylxanthate In Presence Of Surfactants, Ashok Kumar Malik, K. N. Kaul, B. S. Lark, W. Faubel, A. L. J. Rao
Spectrophotometric Determination Of Cobalt, Nickel Palladium, Copper, Ruthenium And Molybdenum Using Sodium Isoamylxanthate In Presence Of Surfactants, Ashok Kumar Malik, K. N. Kaul, B. S. Lark, W. Faubel, A. L. J. Rao
Turkish Journal of Chemistry
A direct method has been developed for the spectrophotometric determination of microamounts of Co(II), Ni(II), Cu(II), Pd(II), Ru(III) and Mo(VI) using sodium isoamylxanthate as a reagent in the presence of surfactant as solubilising agent. The method has been applied to the determination of these metal ions in various alloys and in environmental samples (fly ash).
Unusual Chemical Constituents Of Lotus Garcinii (Fabaceae), Muhammad Shaiq Ali, Farman Ahmad, Viqar Uddin Ahmad, Iqbal Azhar, Khan Usmanghani
Unusual Chemical Constituents Of Lotus Garcinii (Fabaceae), Muhammad Shaiq Ali, Farman Ahmad, Viqar Uddin Ahmad, Iqbal Azhar, Khan Usmanghani
Turkish Journal of Chemistry
The methanol soluble part of Lotus garcinii, belonging to the family Fabaceae, yielded three new interesting metabolites: garceine (1), garoside (2) and garthiol (3), which have never been detected from any natural source. In addition, isophytol, hexadecanoic acid, cholesterol, oleanolic acid, butulinic acid and lupeol were also obtained for the first time from L. garcinii}. All the isolated metabolites were characterized by spectroscopic means.
Determination Of Fluoride And Some Metal Ion Levels In The Drinking Waters In Kayseri Province, Şeri̇fe Tokalioğlu, Uğur Şahi̇n, Şenol Kartal
Determination Of Fluoride And Some Metal Ion Levels In The Drinking Waters In Kayseri Province, Şeri̇fe Tokalioğlu, Uğur Şahi̇n, Şenol Kartal
Turkish Journal of Chemistry
Fluorine is one of the most common elements in the Earth's crust. Fluoride is recognized to be the most effective caries-preventive agent. The main sources of fluoride for people are generally food and drinking water. For this reason, the fluoride and also the metal ion (Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb and Zn) concentrations in the drinking waters collected from the city center of Kayseri and its counties were investigated. In the determination of fluoride and of Na and K, an ion-meter with a combination-fluoride electrode and a flame photometer were used, respectively. The levels of …
Synthesis And Structure Of Systems Containing Pyramidalized And Strained Double Bond: An Investigation On The Cycloaddition Reactions Of Cis- And Trans-3,8-Dicarbomethoxy-3,8-Dihydroheptalene, Nurullah Saraçoğlu, Abdullah Menzek, Meti̇n Balci
Synthesis And Structure Of Systems Containing Pyramidalized And Strained Double Bond: An Investigation On The Cycloaddition Reactions Of Cis- And Trans-3,8-Dicarbomethoxy-3,8-Dihydroheptalene, Nurullah Saraçoğlu, Abdullah Menzek, Meti̇n Balci
Turkish Journal of Chemistry
The cycloaddition reactions of cis-3,8-dicarbomethoxy-3,8-dihydroheptalene cis-2 and trans-3,8-dicarbomethoxy-3,8-dihydroheptalene trans-2 with various dienophiles such as dimethyl acetylenedicarboxylate (DMAD), p-benzoquinone, maleic anhydride, tetracyanoethylene, naphtoquinone gave monoaddition products 15-23. Further addition of benzyne and dimethyl acetylenedicarboxylate to 18 resulted in the formation of the compounds syn-25 and syn-26 having pyramidalized double bonds. The addition of benzyne to 21 and the addition of dimethyl acetylenedicarboxylate to 21, 22 and 23 gave the anti configuration products anti-26, 27 and 28, respectively. X-ray structures of syn-25, syn-26 and anti-26 show the pyramidalized angles to be 16.5^o, 19.9^o and 8.0^o, respectively.
Cross-Correlation Noise Studies In Atomic Magnet-Optic Rotation Spectroscopy, Ahmet T. İnce
Cross-Correlation Noise Studies In Atomic Magnet-Optic Rotation Spectroscopy, Ahmet T. İnce
Turkish Journal of Chemistry
Analytical signals in an Atomic Magneto-Optic Rotation spectrometer are buried in noise at the limit of detection. The noisy analytical signals were analysed by carrying out mathematical correlation of their time domain waveforms. The noise components of signals were removed by auto-correlation to simplify the study. If noise interferes in analytical signals whose source is unclear, a cross-correlation of the output waveform with noise source may identify the source, e.g., mains frequencies and background radio signals. A cross-correlation will reveal whether the two signals are derived from the same source. This can also lead to an improvement in the signal …
Simultaneous Determination Of Inorganic Anions And Organic Acids By Capillary Electrophoresis, Nevi̇n Özteki̇n, F. Bedi̇a Eri̇m Berker
Simultaneous Determination Of Inorganic Anions And Organic Acids By Capillary Electrophoresis, Nevi̇n Özteki̇n, F. Bedi̇a Eri̇m Berker
Turkish Journal of Chemistry
A rapid, easy, and reproducible method for the simultaneous determination of inorganic anions and organic acids is reported. The method is based on the separation of anions in a capillary coated with a cationic polymer, polyethyleneimine (PEI). Four inorganic anions (chloride, sulfate, iodate and phosphate) and eight organic acids (oxalate, tartarate, malate, succinate, citrate, acetate, lactate, and propionate) were separated and quantified within 7 min by using 2,6-pyridinedicarboxylic acid (PDC) as the background electrolyte. The minimum detection limits are 0.67-2.87 \mu g/mL for inorganic ions and 0.38-2.84 \mu g/mL for organic acids. Reproducibilities in migration times (RSD%) for both inorganic …
Analysis Of Polychlorinated Dibenzofurans (Pcdfs) Isomers In Soil Samples, Mustafa Pehli̇van, Erol Pehli̇van
Analysis Of Polychlorinated Dibenzofurans (Pcdfs) Isomers In Soil Samples, Mustafa Pehli̇van, Erol Pehli̇van
Turkish Journal of Chemistry
This study presents an analytical method for the separation of a series of polychlorinated dibenzofurans (PCDFs) emitted to the soil. PCDF contaminants were concentrated from soil samples and isolated from other materials by chromatographic methods and their quantitative determinations were performed by GC/MS (gas chromatography/mass spectroscopy).
Usefulness Of A Technique Based On Negative Corona Discharge For The Degradation Of Selected, Condensed Pahs: Application To The Oxidation Of Anthracene And Similar Structures, D. Tessi̇er, C. Oguic, J. Pinart, J. J. Aaron
Usefulness Of A Technique Based On Negative Corona Discharge For The Degradation Of Selected, Condensed Pahs: Application To The Oxidation Of Anthracene And Similar Structures, D. Tessi̇er, C. Oguic, J. Pinart, J. J. Aaron
Turkish Journal of Chemistry
The usefulness of negative corona discharge for oxidation of condensed polycyclic aromatic hydrocarbons (PAHs), including anthracene, naphthalene and 2,3-benzanthracene, adsorbed on a solid substrate is evaluated. In the case of anthracene, the application of corona discharge under high voltage (10-20 kV) for 10 to 180 min with a current intensity of 5-120 \mu A in a controlled, humid atmosphere leads to the progressive formation of anthraquinone. A kinetic study of the anthracene oxidation shows that the apparent half-lives range from 5 to 48 min, according to the initial anthracene amount (50-5000 nmol), indicating a reaction order between 0 and 1. …
Photochemically-Induced Fluorescence Properties And Determination Of Flufenamic Acid, A Non-Steroidal Anti-Inflammatory Drug, In Urine And Pharmaceutical Preparation, Lei̇la Bettaieb, J. J. Aaron
Photochemically-Induced Fluorescence Properties And Determination Of Flufenamic Acid, A Non-Steroidal Anti-Inflammatory Drug, In Urine And Pharmaceutical Preparation, Lei̇la Bettaieb, J. J. Aaron
Turkish Journal of Chemistry
The photochemically-induced fluorescence (PIF) properties of flufenamic acid (FF), a non-steroidal anti-inflammatory drug (NSAID) were investigated in acidic (pH 1.0) aqueous solutions at room temperature. An optimization procedure, including the effects of UV irradiation time, pH and solvent, was established for the determination of FF. A linear logarithmic calibration plot was obtained over a wide concentration range of four orders of magnitude. A low limit of detection of 0.14 ng/mL was found. The relative standard deviation (RSD) was 6.6% . The PIF method was applied to the quantitative analysis of FF in urine and in a pharmaceutical preparation with satisfactory …