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2014

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Articles 11191 - 11220 of 12299

Full-Text Articles in Physical Sciences and Mathematics

In Vitro Effects Of Pesticide Exposure On The Activity Of The Paraoxonase-1 Enzyme From Sheep Liver Microsomes, Büşra Cebeci̇, Zuhal Alim, Şükrü Beydemi̇r Jan 2014

In Vitro Effects Of Pesticide Exposure On The Activity Of The Paraoxonase-1 Enzyme From Sheep Liver Microsomes, Büşra Cebeci̇, Zuhal Alim, Şükrü Beydemi̇r

Turkish Journal of Chemistry

The organophosphate target enzyme paraoxonase-1 (PON1) has been extensively studied in toxicology. Pesticides are organophosphate compounds that are commonly used in agriculture. They are also used as nerve gases, such as sarin and soman. Therefore, the effects of these compounds on enzymatic activity are well known. In the present study, we investigated the in vitro effects of fenoxaprop-p-ethyl, lambda cyhalothrin, imidacloprid, and dichlorvos pesticides on sheep liver microsomal PON1. The enzyme was purified approximately 141-fold with a specific activity of 1822.22 EU/mg proteins. The pesticides inhibited sheep liver PON1 in vitro, and the IC_{50} values for these compounds were 0.0103, …

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Adsorption Of The Urea Molecule On The B_{12}N_{12} Nanocage, Mohammad Taghi Baei Jan 2014

Adsorption Of The Urea Molecule On The B_{12}N_{12} Nanocage, Mohammad Taghi Baei

Turkish Journal of Chemistry

The adsorption of the urea molecule on the external surface of the B_{12}N_{12} nanocage was investigated using density functional theory (DFT) calculations. Adsorption of urea on the nanocage releases energies of about --23.70 to --29.50 kcal/mol with a significant NBO charge transfer from the urea to the nanocage. It was also found that the urea molecule can be strongly chemisorbed on the surface of the nanocage with Gibbs free energies of -7.91 to -14.81 kcal/mol. The HOMO--LUMO gap of the nanocage does not change significantly upon urea adsorption, while the Fermi level is dramatically changed from -4.27 eV in the …

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Partial Purification And Biochemical Characterization Of An Extremely Thermo- And Ph-Stable Esterase With Great Substrate Affinity, Esra Özbek, Yakup Kolcuoğlu, Leyla Konak, Ahmet Çolak, Fulya Öz Jan 2014

Partial Purification And Biochemical Characterization Of An Extremely Thermo- And Ph-Stable Esterase With Great Substrate Affinity, Esra Özbek, Yakup Kolcuoğlu, Leyla Konak, Ahmet Çolak, Fulya Öz

Turkish Journal of Chemistry

An esterase from a thermophilic bacterium, Geobacillus sp. DF20, was partially purified. Final purification factor was found to be 64.5-fold using Q-Sepharose ion exchange column chromatography. Native polyacrylamide gel electrophoresis indicated the presence of a single active esterase. The substrate specificity of this esterase was high for p-nitrophenyl butyrate (pNPB) substrate. The optimum pH and temperature for the enzyme activity were 7.0 and 50 ^°C, respectively. The pH and heat stability profiles show that this enzyme is more stable under neutral conditions at 50 ^°C. K_m and V_{max} values for this esterase acting on pNPB were 0.12 mM and 54.6 …

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Application Of 3-Aroyl-4(5)-Arylimidazols As Efficient Ligands In Pd-Catalyzed Heck Reactions, Mojtaba Amini, Seyedeh Motahhareh Amini, Bagher Eftekhari-Sis, Ali Keivanloo Jan 2014

Application Of 3-Aroyl-4(5)-Arylimidazols As Efficient Ligands In Pd-Catalyzed Heck Reactions, Mojtaba Amini, Seyedeh Motahhareh Amini, Bagher Eftekhari-Sis, Ali Keivanloo

Turkish Journal of Chemistry

The Heck coupling of haloarenes with various alkenes was successfully performed in the presence of 0.25 mol % PdCl_2 and 0.5 mol % biphenyl-4-yl-[4(5)-(biphenyl-4-yl)-1H-imidazol-2-yl]ketone 2f as a ligand with Na_2CO_3 as optimal base, in a 1:1 mixture of H_2O/DMF as the reaction solvent at 80 ^°C for 8 h. Imidazole 2f was found to be an inexpensive, air-stable, easily available, and efficient ligand in the palladium-catalyzed Heck reactions of aryl iodides (76 %--94 %), bromides (52 %--79 %), and chlorides (40 %--70 %).

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Selective Co Methanation Over Ceo_2--Zro_2-Composed Nio And Co_3o_4 Catalysts, Fi̇li̇z Derekaya, Derya Ermergen Jan 2014

Selective Co Methanation Over Ceo_2--Zro_2-Composed Nio And Co_3o_4 Catalysts, Fi̇li̇z Derekaya, Derya Ermergen

Turkish Journal of Chemistry

CeO_2--ZrO_2-composed NiO and Co_3O_4 catalysts were prepared by 3 different methods. Both CO methanation and selective CO methanation were carried out. All catalysts were prepared by (1) co-precipitation, (2) surfactant-assisted co-precipitation, and (3) surfactant-assisted co-precipitation with ultrasound mixing methods. Catalysts were characterized by using N_2 physisorption, XRD, SEM, TEM, and TPR-H_2 techniques. The highest surface area value, uniform pore size distribution, and pores having small diameters were observed for the catalysts prepared by using the surfactant and ultrasound. The NiO/CeO_2/ZrO_2 prepared by the surfactant-assisted co-precipitation was the most active catalyst for CO methanation. It gave 50 % CO conversion to …

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Antioxidant, Anticholinesterase, And Antimicrobial Activities And Fatty Acid Constituents Of Achillea Cappadocica Hausskn. Et Bornm., Abdulselam Ertaş, Mehmet Boğa, Nesri̇n Haşi̇mi̇, Yeter Yeşi̇l, Ahmet Ceyhan Gören, Gülaçti Topçu, Ufuk Kolak Jan 2014

Antioxidant, Anticholinesterase, And Antimicrobial Activities And Fatty Acid Constituents Of Achillea Cappadocica Hausskn. Et Bornm., Abdulselam Ertaş, Mehmet Boğa, Nesri̇n Haşi̇mi̇, Yeter Yeşi̇l, Ahmet Ceyhan Gören, Gülaçti Topçu, Ufuk Kolak

Turkish Journal of Chemistry

This study was the first fatty acid analysis and biological activity report on an endemic Achillea species, Achillea cappadocica Hausskn. et Bornm. The major compounds in the fatty acid were identified as oleic (34.7 %), palmitic (23.1 %), and linoleic acids (20.6 %). The methanol and water extracts indicated higher ABTS cation radical scavenging activity than that of \alpha-tocopherol and BHT at 100 \mu g/mL. The acetone extract showed 70.62 % inhibitory activity against butyrylcholinesterase at 200 \mu g/mL. The acetone and methanol extracts exhibited moderate antimicrobial activity.

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Catalytic Conversion Of Carbon Dioxide Into Cyclic Carbonates By Cu(Ii) And Ni(Ii) Acetylacetonates Anchored Onto Siral 80, Senem Coşkun, Zeynep Taşci, Mahmut Ulusoy, Mürüvvet Yurdakoç Jan 2014

Catalytic Conversion Of Carbon Dioxide Into Cyclic Carbonates By Cu(Ii) And Ni(Ii) Acetylacetonates Anchored Onto Siral 80, Senem Coşkun, Zeynep Taşci, Mahmut Ulusoy, Mürüvvet Yurdakoç

Turkish Journal of Chemistry

Ni and Cu acetylacetonates were anchored onto Siral 80 and used in the catalytic conversion of carbon dioxide. The catalysts were characterized by several methods such as XRD, FTIR, SEM, and TGA/DTG. The catalytic domains of the prepared heterogeneous complexes and their homogeneous counterparts were examined for the conversion reaction of carbon dioxide into cyclic carbonates in the presence of different additives (1.5 MPa CO_2 pressure, 100 ^°C, and 2 h). Good to excellent conversions were observed using Siral 80/APTES/Cu(acac)_2 catalysts and butylmethylimidazolium hexafluorophosphate, [bmim]PF_6, ionic liquid from the reaction of CO_2, and different epoxides. Modification with APTES made the …

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Oxidation Of Hydrocarbons With Tetra-N-Butylammonium Peroxy Monosulfate Catalyzed By \Beta-Tetrabromo-Meso-Tetrakis(4-Methoxyphenyl)- And \Beta-Tetrabromo-Meso-Tetraphenylporphyrinatomanganese(Iii), Saeed Rayati, Saeed Zakavi, Hossein Valinejad Jan 2014

Oxidation Of Hydrocarbons With Tetra-N-Butylammonium Peroxy Monosulfate Catalyzed By \Beta-Tetrabromo-Meso-Tetrakis(4-Methoxyphenyl)- And \Beta-Tetrabromo-Meso-Tetraphenylporphyrinatomanganese(Iii), Saeed Rayati, Saeed Zakavi, Hossein Valinejad

Turkish Journal of Chemistry

\beta-Tetrabromo-meso-tetrakis(4-methoxyphenyl)porphyrin, H_2T(4-OCH_3P)PBr_4, was synthesized and characterized by UV-Vis and ^1H NMR spectroscopy. Oxidation of alkanes and olefins with tetra-n-butylammonium peroxymonosulfate (n-Bu_4NHSO_5) was studied in the presence of MnT(4-OCH_3P)PBr_4(OAc) and MnTPPPBr_4(OAc) (TPP = meso-tetraphenylporphyrin). While significance differences were observed between the catalytic activities of the title complexes in the oxidation of alkanes, the 2 manganese porphyrins showed comparable activities in oxidation of most of the olefins used. However, the latter showed greater catalytic performance in the oxidation of the hydrocarbons. Moreover, the oxidative degradation of the former (60 %) was greater than that of the latter (45 %) in the oxidation …

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Organic Biomolecules Bind To Phosphate Through Borate Linkages In Aqueous Solutions, Nazi̇k Aydoğmuş, Dursun Ali̇ Köse, Michael Andrew Beckett, Bi̇rgül Karan Jan 2014

Organic Biomolecules Bind To Phosphate Through Borate Linkages In Aqueous Solutions, Nazi̇k Aydoğmuş, Dursun Ali̇ Köse, Michael Andrew Beckett, Bi̇rgül Karan

Turkish Journal of Chemistry

Solutions of salicyclic, ascorbic, and citric acids were reacted with boric acid, followed by NaH_2PO_4. The products, triphosphateborate ester of salicylic acid (1), orthosphateborate ester of ascorbic acid (2), triphosphateborate ester of ascorbic acid (3), and orthosphateborate ester of citric acid (4), were flash precipitated with cold acetone and characterised by microanalysis, thermal analysis, FT-IR, Raman, ^{11}B NMR, ^{31}P MAS NMR, and mass spectroscopic techniques. Analytical results indicated the presence of --C--O--B--O--P-- linkages with the attached phosphate groups varying between orthophosphate and triphosphate, depending on the starting material. The biomolecules studied in this work may serve as models in the …

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Poly(Vinyl Chloride) Functionalization By Aliphatic And Aromatic Amines: Application To The Extraction Of Some Metal Cations, Fayçel Ammari, Faouzi Meganem Jan 2014

Poly(Vinyl Chloride) Functionalization By Aliphatic And Aromatic Amines: Application To The Extraction Of Some Metal Cations, Fayçel Ammari, Faouzi Meganem

Turkish Journal of Chemistry

The aim of this study was to evaluate the efficiency of 3 new polymers obtained by functionalization of a commercial poly(vinyl chloride) by grafting amino-alkyl and amino-aryl groups to extract some metal cations from aqueous solutions. The percentage of extraction was determined by comparing the initial electrical conductivity of the aqueous solution containing the studied metal and that of the aqueous solution at the extraction equilibrium. One of the obtained polymers gave an extraction ratio of Sn^{2+} = 87.1 %, which highlight the importance of the substitution of chlorine atoms by diethylenetriamine groups. These results were compared with those obtained …

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Aqueous Dabco, An Efficient Medium For Rapid Organocatalyzed Knoevenagel Condensation And The Gewald Reaction, Mohammad Saeed Abaee, Somayeh Cheraghi Jan 2014

Aqueous Dabco, An Efficient Medium For Rapid Organocatalyzed Knoevenagel Condensation And The Gewald Reaction, Mohammad Saeed Abaee, Somayeh Cheraghi

Turkish Journal of Chemistry

In the presence of water and 1,4-diazabicyclo[2.2.2]octane, several aldehydes and cyclic ketones underwent efficient Knoevenagel condensation with malononitrile and ethyl cyanoacetate to produce the respective \alpha.\beta-unsaturated systems within fairly short time periods. As a result, high yields of conjugated products were easily obtained. Products could be engaged in a Gewald reaction, either stepwise or in situ, to produce efficiently their respective 2-aminothiophenes within 4--7 h.

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Thermal Conversion Of Glycerol To Value-Added Chemicals: Pyridine Derivatives By One-Pot Microwave-Assisted Synthesis, Duygu Bayramoğlu, Gökay Gürel, Ali̇ Sinağ, Mustafa Güllü Jan 2014

Thermal Conversion Of Glycerol To Value-Added Chemicals: Pyridine Derivatives By One-Pot Microwave-Assisted Synthesis, Duygu Bayramoğlu, Gökay Gürel, Ali̇ Sinağ, Mustafa Güllü

Turkish Journal of Chemistry

One-pot syntheses of the value-added heterocyclic compounds 3-methylpyridine and pyridine using a renewable chemical, glycerol, were achieved in acidic medium by thermal conversion reactions. Condensation/cyclization reactions of the thermal degradation products of glycerol were investigated in situ using different ammonia and acidic moiety producing inorganic ammonium salts under pyrolysis or microwave heating conditions. The reaction parameters were studied in detail and satisfying product yields up to 72 % were obtained under optimized conditions. Structural identification of all compounds was accomplished by spectroscopic methods.

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Synthesis And Characterization Of A Novel 3-Amino-1,2,4-Triazole Lead(Ii) Coordination Polymer, Şebnem Esen Sözerli̇, Arzu Özen, İbrahi̇m Kani̇, Deni̇z Demi̇r Jan 2014

Synthesis And Characterization Of A Novel 3-Amino-1,2,4-Triazole Lead(Ii) Coordination Polymer, Şebnem Esen Sözerli̇, Arzu Özen, İbrahi̇m Kani̇, Deni̇z Demi̇r

Turkish Journal of Chemistry

A novel [Pb_2(\mu-atrz)_2(\mu-CH_3COO)(CH_3COO)]_n (atrz = 3-amino-1,2,4-triazole) complex was synthesized and characterized by IR spectroscopy, thermogravimetric analysis, and single crystal X-ray diffraction. The molecular structure shows that the complex is a coordination polymer in which there are 2 different lead(II) ions with coordination number of 5, Pb(2), and, with a coordination number of 4, Pb(1). Each atrz acts as a bridging ligand between 2 Pb(II) ions through the 2 adjacent nitrogen atoms of the triazole ring. The acetate anions show different types of coordination mode: one acts as a bridge by coordination of the same oxygen atom with Pb(II) ions and …

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N-Heterocyclic Carbene (Nhc) Palladium(Ii) Complexes Bearing Chiral Oxazoline Ligands And Their Catalytic Activities In Allylic Alkylation Reactions, Serpi̇l Deni̇zalti, Hayati̇ Türkmen, Beki̇r Çeti̇nkaya Jan 2014

N-Heterocyclic Carbene (Nhc) Palladium(Ii) Complexes Bearing Chiral Oxazoline Ligands And Their Catalytic Activities In Allylic Alkylation Reactions, Serpi̇l Deni̇zalti, Hayati̇ Türkmen, Beki̇r Çeti̇nkaya

Turkish Journal of Chemistry

NHC--Pd(II) complexes bearing a chiral oxazoline ligand (IIIa--f) were synthesized by cleavage of dimeric palladium complexes with the oxazoline ligand. They were fully characterized by ^1H and ^{13}C NMR and elemental analyses. The catalytic activity of the complexes (IIIa--f) in allylic alkylation reactions was evaluated. The complex IIIa was found to be the most active catalyst. Very low ee values indicate that the oxazoline is dissociated from the active catalytic species.

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Linear Assembly And 3d Networks Of Peptide Modified Gold Nanoparticles, Şaban Kalay, Clement Blanchet, Mustafa Çulha Jan 2014

Linear Assembly And 3d Networks Of Peptide Modified Gold Nanoparticles, Şaban Kalay, Clement Blanchet, Mustafa Çulha

Turkish Journal of Chemistry

The charge and size of molecules chemically attached to nanoparticles (NPs) play an important role in their interaction behavior in suspensions. Gold nanoparticles (AuNPs) were modified systematically with peptides and the modification was verified with surface-enhanced Raman scattering (SERS). The behavior of the modified AuNPs in suspension and at the liquid--solid interface was monitored using small angle X-ray scattering (SAXS), UV/Vis spectroscopy and dynamic light scattering (DLS) in suspension, and atomic force microscopy (AFM) at the solid--liquid interface. It was found that while negatively charged peptide modified AuNPs behave very similar to citrate reduced AuNPs due to their negatively charged …

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Binding Of Flavanone With \Beta-Cd/Ctdna: A Spectroscopic Investigation, Chandrasekaran Sowrirajan, Sameena Yousuf, Muthu Vijayan Enoch Israel Vijayaraj Jan 2014

Binding Of Flavanone With \Beta-Cd/Ctdna: A Spectroscopic Investigation, Chandrasekaran Sowrirajan, Sameena Yousuf, Muthu Vijayan Enoch Israel Vijayaraj

Turkish Journal of Chemistry

The inclusion complexation of flavanone with \beta-cyclodextrin was studied by ultraviolet absorption, steady state fluorescence, time-resolved fluorescence, and 2D ROESY nuclear magnetic resonance spectroscopic techniques. A 1:1 stoichiometric ratio was determined for the inclusion of flavanone with \beta-cyclodextrin. The Stern--Volmer constant for the accessible fraction of the binding of flavanone with \beta-cyclodextrin, and the binding constant for the flavanone--\beta-cyclodextrin complex are reported. The flavanone--\beta-cyclodextrin inclusion complex was characterized by 2D ROESY NMR spectroscopy. The binding of flavanone with ctDNA and the effect of \beta-cyclodextrin on the binding of flavanone to ctDNA were studied by absorption and fluorescence techniques. Binding constants …

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Synthesis Of Novel Triazoles Bearing 1,2,4-Oxadiazole And Phenylsulfonyl Groups By 1,3-Dipolar Cycloaddition Of Some Organic Azides And Their Biological Activities, Yaşar Dürüst, Hamza Karakuş, Muhsi̇ne Zeynep Yavuz, Ali̇ Akçahan Gepdi̇remen Jan 2014

Synthesis Of Novel Triazoles Bearing 1,2,4-Oxadiazole And Phenylsulfonyl Groups By 1,3-Dipolar Cycloaddition Of Some Organic Azides And Their Biological Activities, Yaşar Dürüst, Hamza Karakuş, Muhsi̇ne Zeynep Yavuz, Ali̇ Akçahan Gepdi̇remen

Turkish Journal of Chemistry

1,3-Dipolar cycloaddition of 5-azidomethyl-3-p-substituted phenyl-1,2,4-oxadiazoles to phenyl vinyl sulfone and bismaleimide gives rise straightforwardly to 1-((3-(p-substituted) phenyl-1,2,4-oxadiazol-5-yl)methyl)-4-(phenylsul\-fonyl)-4,5-dihydro-1H-1,2,3-triazoles and bisdihydropyrrolo[3,4-d][1,2,3]triazole-4,6(3aH,5H)-diones. The structures of the new cycloadducts were elucidated by means of IR, NMR (^1H, ^{13}C, 2D), mass spectra, and physical characteristics (mp and R_f values). In addition, anticancer activities of the cycloadducts against MCF-7 cells were also investigated.

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Simultaneous Determination Of Dexpanthenol, Lidocaine Hydrochloride, And Mepyramine Maleate In Combined Pharmaceutical Gel By Capillary Electrophoresis, Gülden Akyil, Hayri̇ye Eda Şatana Kara, Sezen Yarimkaya Baş, Nusret Ertaş, Ni̇lgün Günden Göğer Jan 2014

Simultaneous Determination Of Dexpanthenol, Lidocaine Hydrochloride, And Mepyramine Maleate In Combined Pharmaceutical Gel By Capillary Electrophoresis, Gülden Akyil, Hayri̇ye Eda Şatana Kara, Sezen Yarimkaya Baş, Nusret Ertaş, Ni̇lgün Günden Göğer

Turkish Journal of Chemistry

A new capillary electrophoresis method was developed for the simultaneous determination of dexpanthenol (DEX), lidocaine (LID), and mepyramine (MEP) in pharmaceutical preparations. The best results were obtained using 20 mM (pH 3.0) phosphate buffer as the background electrolyte. Separation was obtained using a fused-silica capillary (75 \mu m internal diameter, 50 cm total length, 41 cm effective length) and a potential of +30 kV at 20 °C. Standards and samples were injected using a pressure injection at 50 mbar for 5 s and the analytes were monitored at a detection wavelength of 200 nm. Under optimum conditions, migration times were …

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Ultrarapid Catalytic Reduction Of Some Dyes By Reusable Novel Erythromycin-Derived Silver Nanoparticles, Yasmeen Junejo, Abdulhadi̇ Baykal Jan 2014

Ultrarapid Catalytic Reduction Of Some Dyes By Reusable Novel Erythromycin-Derived Silver Nanoparticles, Yasmeen Junejo, Abdulhadi̇ Baykal

Turkish Journal of Chemistry

A novel green approach for the synthesis of silver nanoparticles using erythromycin as a reducing/capping agent is presented. Erythromycin-derived silver nanoparticles were characterized by ultraviolet-visible spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy, X-ray powder diffraction, and Fourier transform infrared spectroscopy. Monodispersed silver nanoparticles showed excellent and promising catalytic activity for reduction of 3 differently charged dyes (eosin B, methylene blue, and rose bengal) in the presence of NaBH_4. The study revealed that 100% reduction of these dyes can be achieved efficiently in just 150--250 s. They were easily recovered from the reaction medium and were reused 5 times, …

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Graphene Oxide--Magnetite Nanocomposite As An Efficient And Magnetically Separable Adsorbent For Methylene Blue Removal From Aqueous Solution, Kadem Meral, Önder Meti̇n Jan 2014

Graphene Oxide--Magnetite Nanocomposite As An Efficient And Magnetically Separable Adsorbent For Methylene Blue Removal From Aqueous Solution, Kadem Meral, Önder Meti̇n

Turkish Journal of Chemistry

We report a facile method to produce a magnetically separable graphene oxide--magnetite nanocomposite (GO--Fe_3O_4) and its adsorption performance in methylene blue (MB) removal from aqueous solution. The GO--Fe_3O_4 nanocomposite was synthesized by a solution-phase self-assembly method including the incorporation of monodisperse Fe_3O_4 nanoparticles (NPs) and GO in a dimethylformamide/chloroform mixture under sonication. The successfully decorating GO sheet with monodisperse Fe_3O_4 NPs was proved by TEM study. ICP--OES data of the GO--Fe_3O_4 nanocomposite show that the GO--Fe_3O_4 nanocomposite consists of 21 wt% Fe_3O_4 NPs, which is sufficient for its magnetic separation from aqueous solution. The spectroscopic studies reveal that the GO--Fe_3O_4 …

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Study On Transportation Of Phenol Through A Nanotubule Membrane, Yue Liu, Li Xie, Xiaoxue Fan, Dingyan Fan, Shasheng Huang Jan 2014

Study On Transportation Of Phenol Through A Nanotubule Membrane, Yue Liu, Li Xie, Xiaoxue Fan, Dingyan Fan, Shasheng Huang

Turkish Journal of Chemistry

Gold nanochannels were prepared by plating electrolessly gold within the pores of polycarbonate filter membranes (PCTMs). These PCTMs with cylindrical Au nanotubules of uniform radius and high density can be used as a convenient model system to investigate the mechanism of particle transport through nanotubules. The transport properties of phenol through a modified Au nanotubule membrane were studied. The permeate flux of phenol transport through the nanotubule membrane can be spatially and temporally manipulated by controlling the magnitude and direction of the current applied across the separation cell, and the electroosmotic flow (EOF) was investigated by measuring the flux of …

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Synthesis And Characterization Of Magnesium Borate Minerals Of Admontite And Mcallisterite Obtained Via Ultrasonic Mixing Of Magnesium Oxide And Various Sources Of Boron: A Novel Method, Azmi̇ Seyhun Kipçak, Emek Moroydor Derun, Sabri̇ye Pi̇şki̇n Jan 2014

Synthesis And Characterization Of Magnesium Borate Minerals Of Admontite And Mcallisterite Obtained Via Ultrasonic Mixing Of Magnesium Oxide And Various Sources Of Boron: A Novel Method, Azmi̇ Seyhun Kipçak, Emek Moroydor Derun, Sabri̇ye Pi̇şki̇n

Turkish Journal of Chemistry

Magnesium borates can be used as detergent compounds or hydrocarbon catalyzers and in the ceramics industry for superconductor material manufacture owing to their high elastic coefficient and resistance to corrosion at high temperatures. In the present study, the synthesis of magnesium borate was facilitated via a novel ultrasonic method of mixing and the identification and characterization of the material were carried out via X-Ray diffraction (XRD), Fourier transform infrared (FT-IR), and Raman spectroscopies, and the B_2O_3 content was determined through titration. The surface morphology was investigated using scanning electron microscopy (SEM). The results of the XRD analysis identified the synthesized …

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The Effects Of Ionic Strength And Temperature On The Dissociation Constants Of Adefovir And Cidofovir Used As Antiviral Drugs, Hasan Atabey, Hayati̇ Sari Jan 2014

The Effects Of Ionic Strength And Temperature On The Dissociation Constants Of Adefovir And Cidofovir Used As Antiviral Drugs, Hasan Atabey, Hayati̇ Sari

Turkish Journal of Chemistry

The effects of ionic strength and temperature on the dissociation constants of adefovir (PMEA) and cidofovir (HPMPC) used as antiviral drugs were studied at 298 K, 308 K, and 318 K in aqueous media and at different ionic strength backgrounds of NaCl potentiometrically. The dissociation constants of the ligands were determined via the calculation of the titration data with the SUPERQUAD computer program. The thermodynamic parameters (\Delta G, \Delta H, and \Delta S) for all species were calculated. The dissociation order of nitrogen and oxygen atoms in the ligands according to proton affinities values were obtained using PM6 semiempirical methods. …

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Synthesis, Anticandidal Activity, And Cytotoxicity Of Some Thiazole Derivatives With Dithiocarbamate Side Chains, Leyla Yurttaş, Yusuf Özkay, Fati̇h Demi̇rci̇, Gamze Göger, Şafak Ulusoylar Yildirim, Usama Abu Mohsen, Ömer Öztürk, Zafer Asim Kaplancikli Jan 2014

Synthesis, Anticandidal Activity, And Cytotoxicity Of Some Thiazole Derivatives With Dithiocarbamate Side Chains, Leyla Yurttaş, Yusuf Özkay, Fati̇h Demi̇rci̇, Gamze Göger, Şafak Ulusoylar Yildirim, Usama Abu Mohsen, Ömer Öztürk, Zafer Asim Kaplancikli

Turkish Journal of Chemistry

Some thiazole derivatives bearing dithiocarbamic acid esters were synthesized in order to investigate their anticandidal activity and cytotoxicity. The structures of the obtained final compounds (6a--j) were confirmed by spectral data (IR, ^1H NMR, ^{13}C NMR, and MS) and elemental analysis. The anticandidal activity of the compounds was determined (6a--j) using the microbroth dilution method and their cytotoxicity was evaluated according to the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay against normal cells. Contrary to expectations, weak antifungal activity was observed with IC_{50} values ranging between 30 and 403 \mu g/mL.

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Green Synthesis Of Fe_3o_4 Nanoparticles By One-Pot Saccharide-Assisted Hydrothermal Method, Ayşe Demi̇r, Abdulhadi̇ Baykal, Hüseyi̇n Sözeri̇ Jan 2014

Green Synthesis Of Fe_3o_4 Nanoparticles By One-Pot Saccharide-Assisted Hydrothermal Method, Ayşe Demi̇r, Abdulhadi̇ Baykal, Hüseyi̇n Sözeri̇

Turkish Journal of Chemistry

A saccharide-assisted hydrothermal route starting from a single iron precursor was employed to study the influence of reducing saccharides on the formation of iron oxide (Fe_3O_4) nanoparticles (NPs). Fe_3O_4 NPs, which were confirmed by X-ray diffraction analysis, were successfully synthesized by a hydrothermal method in which mannose, maltose, lactose, and galactose served as reducing agents. The formation of Fe_3O_4 NPs was also confirmed by Fourier transform infrared spectroscopy. Samples exhibited different crystallite sizes estimated based on line profile fitting as 12 \pm 2, 9 \pm 2, 13 \pm 3, and 9 \pm 3 nm for mannose, maltose, lactose, and galactose, …

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Graphite Oxide As An Efficient Solid Reagent For Esterification Reactions, Maryam Mirzaaghayan, Rabah Boukherroub, Mahshid Rahimifard Jan 2014

Graphite Oxide As An Efficient Solid Reagent For Esterification Reactions, Maryam Mirzaaghayan, Rabah Boukherroub, Mahshid Rahimifard

Turkish Journal of Chemistry

Esterification of organic acids with alcohols under mild conditions in high yields using graphite oxide, a readily available and inexpensive material, as an effective reagent is described.

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Convenient Method For Synthesis Of Various Fused Heterocycles Via Utility Of 4-Acetyl-5-Methyl-1-Phenyl-Pyrazole As Precursor, Sobhi Mohamed Gomha, Ahmad Sami Shawali, Abdou Osman Abdelhamid Jan 2014

Convenient Method For Synthesis Of Various Fused Heterocycles Via Utility Of 4-Acetyl-5-Methyl-1-Phenyl-Pyrazole As Precursor, Sobhi Mohamed Gomha, Ahmad Sami Shawali, Abdou Osman Abdelhamid

Turkish Journal of Chemistry

A new, less expensive, solvent-free procedure was developed for the synthesis of some new derivatives of various fused heterocyclic ring systems, namely azolopyridazine, azolotriazine, azinotriazine, thienopyridine, and pyrazolopyridine. The structures of the products prepared were established by their spectral data and elemental analyses. Eight compounds were evaluated for their in vitro antimicrobial activity. Some of the tested compounds exhibited moderate to significant antibacterial and antifungal activities.

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Rosmarinic Acid: A Potent Carbonic Anhydrase Isoenzymes Inhibitor, Meryem Topal, İlhami̇ Gülçi̇n Jan 2014

Rosmarinic Acid: A Potent Carbonic Anhydrase Isoenzymes Inhibitor, Meryem Topal, İlhami̇ Gülçi̇n

Turkish Journal of Chemistry

Rosmarinic acid is a water-soluble ester of caffeic acid and 3,4-dihydroxyphenyllactic acids, and is mainly found in plant species including Boraginaceae and Lamiaceae. In this research, we determined the inhibition property of rosmarinic acid on carbonic anhydrase isoenzymes I and II (hCA I and II) purified from human erythrocytes by using Sepharose-4B affinity column chromatography. hCA I and II isoenzymes were obtained with a yield of 57.9% and 67.2% and 76.5- and 509.3-fold purification of each isoenzyme, respectively. In order to show the purity of the isoenzymes, SDS-PAGE was performed and one band was observed. In vitro inhibition of both …

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History, Development, And A New Concept Of Phthalocyanines In Turkey, Özer Bekaroğlu Jan 2014

History, Development, And A New Concept Of Phthalocyanines In Turkey, Özer Bekaroğlu

Turkish Journal of Chemistry

This paper reviews the history of phthalocyanines in Turkey. Phthalocyanines are chemical compounds that were accidently discovered nearly a century ago. The relevant research and articles have grown dramatically in Turkey since our first paper on them containing four [15]crown[5] published in 1986. The ball-type phthalocyanines were produced and published as a new concept in phthalocyanine chemistry for the first time by our group in Turkey in 2006. Unfortunately, with the exception of our work on this subject, almost no papers have been published in Turkey or in other countries since then. We strongly urge scientists to consider working on …

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N-Bridged Dimers Of Tetrapyrroles Complexed By Transition Metals: Syntheses, Characterization Methods, And Uses As Oxidation Catalysts, Ümi̇t İşci̇, Fabienne Dumoulin, Alexander B. Soroki̇n, Vefa Ahsen Jan 2014

N-Bridged Dimers Of Tetrapyrroles Complexed By Transition Metals: Syntheses, Characterization Methods, And Uses As Oxidation Catalysts, Ümi̇t İşci̇, Fabienne Dumoulin, Alexander B. Soroki̇n, Vefa Ahsen

Turkish Journal of Chemistry

N-bridged dimers of tetrapyrroles complexed by transition metals have been known for nearly four decades, and gained renewed attention when their powerful oxidation properties were recently evidenced. This article is a state of the art review of the reported complexes and of their synthetic methods. Beyond classical chemistry characterization tools, specific methods appropriate to their structure are used and are presented in detail. Finally, their uses and importance of oxidation catalysts are reviewed.

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