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1997

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Articles 241 - 270 of 296

Full-Text Articles in Chemistry

Features Of Graft Copolymer Formation Through Reaction Of Functionalized Polyolefins With Poly-\Epsilon-Caprolactam, Elisa Passaglia, Francesco Picchioni, Mauro Aglietto, Giocomo Ruggeri, Francesco Ciardelli Jan 1997

Features Of Graft Copolymer Formation Through Reaction Of Functionalized Polyolefins With Poly-\Epsilon-Caprolactam, Elisa Passaglia, Francesco Picchioni, Mauro Aglietto, Giocomo Ruggeri, Francesco Ciardelli

Turkish Journal of Chemistry

The reaction in the melt of polyolefins containing 2-diethylsuccinate groups (DES) with poly-\epsilon-caprolactam (PA6) to give a graft copolymer was investigated under different conditions. Even using a large excess of DES groups over the PA6 terminal amino groups the graft copolymer yield resulted only partial thus suggesting a kinetic control of the reaction. The effect of various catalysts was then examined taking into account results obtained in a model reaction between a low molecular weight amine and diethylsuccinate. The results are discussed in terms of side reactions and miscibility of the pristine polymers.

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Phase Transition Of Hydrolyzed Polyacrylamide Gels In Aqueous Solutions Of Poly(Ethylene Glycol), Nilhan Kayaman, Oğuz Okay, B. M. Baysal Jan 1997

Phase Transition Of Hydrolyzed Polyacrylamide Gels In Aqueous Solutions Of Poly(Ethylene Glycol), Nilhan Kayaman, Oğuz Okay, B. M. Baysal

Turkish Journal of Chemistry

Hydrolyzed polyacrylamide gels immersed in aqueous solutions of poly(ethylene glycol) (PEG) of molecular weight 300 exhibit a discontinuous volume change upon continuous increase of the PEG concentration in the external solution. As the duration of hydrolysis increases, that is, as the proportion of the ionic groups on the network chains increases, the critical concentration of PEG required for a discontinuous volume change rises and, also, the magnitude of the volume collapse becomes larger. Experimental results indicate that the gel collapse in PEG solution is due to the osmotic deswelling of the ionic gel rather than due to a complex formation …

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Immobilization Of Glucose Oxidase And Urease In Hydrogel Matrices, İhsan Gürel, M.Yakup Arica, Vasıf Hasirci Jan 1997

Immobilization Of Glucose Oxidase And Urease In Hydrogel Matrices, İhsan Gürel, M.Yakup Arica, Vasıf Hasirci

Turkish Journal of Chemistry

Immobilization of glucose oxidase and urease in hydrogels of 2-hydroxyethyl methacrylae, and N-vinyl pyrrolidone (NVP) was achieved by irradiation (using UV kand \gamma- rays). The effect of radiation on entrapment efficiencies, retention of activities and swelling rates was obtained. To optimize the system, duration of exposure, reaction temperature, co-monomer concentrations, initiator and cross linker compositions were varied. The repeated reusability of the generated products was also tested. It was found that\gamma-irradiation at very low temperatures did not have a detrimental effect on the enzyme activity. Incorporation of more hydrophilic monomer (NVP), influenced matrix morphology and entrapment efficiencies and retained enzyme …

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Potentiometric And Spectroscopic Determinaton Of Acid Dissociation Constants Of Some Phenols And Salicylic Acids, Rahmiye Aydin, Ulviye Özer, Naciye Türkel Jan 1997

Potentiometric And Spectroscopic Determinaton Of Acid Dissociation Constants Of Some Phenols And Salicylic Acids, Rahmiye Aydin, Ulviye Özer, Naciye Türkel

Turkish Journal of Chemistry

The dissociation constant of the catechol derivatives 4-nitrocatechol (NCAT), 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid (3,4-DBHA), 3,4-dihydroxyhenylacetic acid (3,4-DPHA) and 3,4-dihydroxycinnamic acid (3,4-DHCA) were identified in 0.1M NaClO_4 ionic medium, at t=25^{\circ}C, by potentiometry. In addition, the first and second dissociation constants of the salicylic acid derivatives 5-nitrosalicylic acid (5-NSA), 4-hydroxysalicylic acid (4-HSA) 5-nitrosalicylic acid (5-HSA) were also determined by potentiometry. Furthermore, the second acid dissociation constants of these ligands were evaluated in I=0.1M NaClO_4 ionic medium, at a temperature of 25^{\circ}C by computer analysis of spectroscopic data.

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Preparation Of Powder Precursors And Evaporation Of Photoconductive Indium Sulfide Films, Chris Barber, Robert Engelken, Brandon Kemp, Wasim Aleem, Imran Khan, Chris Edrington, Michael Buck, Clayton Workman, Anup Thapa, Tom Jakobs Jan 1997

Preparation Of Powder Precursors And Evaporation Of Photoconductive Indium Sulfide Films, Chris Barber, Robert Engelken, Brandon Kemp, Wasim Aleem, Imran Khan, Chris Edrington, Michael Buck, Clayton Workman, Anup Thapa, Tom Jakobs

Journal of the Arkansas Academy of Science

We have demonstrated significant photoconductance in indium sulfide thin films prepared by thermal vacuum evaporation ofIn2$3 powders synthesized in-house by chemical precipitation ofInCl3 or In(CH3COO)3, and (NH4)2S or Na2S. The Delta G lambda/Gdark values have been as high as 0.1 in the initial unoptimized films. Excess sulfur (via a mixture of polysulfide and sulfide ions in the synthesis bath) appears to be important in achieving reproducible and large photoconductivities. In2S3 is particularly attractive as a lower toxicity alternative to CdS in optoelectronic applications such as photovoltaic and photoconductive cells.

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Electron Shock Waves: Effect Of Current On Electron Temperature And Density, Mostafa Hemmati, Mathues Shane Doss Jan 1997

Electron Shock Waves: Effect Of Current On Electron Temperature And Density, Mostafa Hemmati, Mathues Shane Doss

Journal of the Arkansas Academy of Science

In our attempt to find analytical solutions for breakdown waves, we employ a set of three-component fluid equations. In addition to reporting the method of integration of electron fluid dynamical equations through the dynamical transition region (sheath region), the wave profile for ionization rate, electron number density and electron temperature inside the sheath will be discussed. Also, the effect of the current on electron temperature, electron number density and ionization rate will be reported.

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Acidity Studies Of Deuterated Acids And Bases Commonly Used As Buffers In Nmr Studies, Rose M. Mcconnell, Walter E. Godwin, Brant Stanley, M. Shane Green Jan 1997

Acidity Studies Of Deuterated Acids And Bases Commonly Used As Buffers In Nmr Studies, Rose M. Mcconnell, Walter E. Godwin, Brant Stanley, M. Shane Green

Journal of the Arkansas Academy of Science

Structure based drug development is currently considered to be an important strategy for drug discovery. This strategy requires that critical knowledge of the three dimensional binding site on receptor molecules be known. NMR studies are frequently employed to ascertain important structural data on individual proteins as well as complexes of proteins with ligands. Deuterium labeled acids and bases are frequently used as buffers in deuterium oxide solutions for NMR studies on the structural conformations of bioactive molecules. Since pH is an important factor in any study of the conformational and stereochemical aspects of biologically active molecules, deuterated buffers are an …

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Artificial Neural Networks Used To Predict Electrical Properties Of Polymers, Sanjay K. Mitra, Qing Luo, Jerry A. Darsey Jan 1997

Artificial Neural Networks Used To Predict Electrical Properties Of Polymers, Sanjay K. Mitra, Qing Luo, Jerry A. Darsey

Journal of the Arkansas Academy of Science

The ability to predict properties of molecules prior to their synthesis can be of great importance in optimizing their design. Substantial savings in time as well as cost can be achieved if some desired properties can be predicted prior to the synthesis of the molecule. The outer orbitals of a molecule are primarily responsible for many different properties of the molecules. These outer orbital parameters can be utilized by an intelligent computing system like an Artificial Neural Network to extract necessary knowledge about the properties of the molecule. An Artificial Neural Network was trained to extract electrical parameters of several …

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New Studies Of Polyfuran And Polymers Of 3-Substituted Furan Rings, Rose M. Mcconnell, Walter E. Godwin, Bradley Phillips Jan 1997

New Studies Of Polyfuran And Polymers Of 3-Substituted Furan Rings, Rose M. Mcconnell, Walter E. Godwin, Bradley Phillips

Journal of the Arkansas Academy of Science

No abstract provided.

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Reductive Dechlorinatin Of A 2-Chloronicotinic Acid Under Finkelstein Conditions, Frank L. Setliff, Leslie B. Coop Jan 1997

Reductive Dechlorinatin Of A 2-Chloronicotinic Acid Under Finkelstein Conditions, Frank L. Setliff, Leslie B. Coop

Journal of the Arkansas Academy of Science

No abstract provided.

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Efficient And General Synthesis Of Novel Β-Polyfluoroalkoxy Vinamidinium Salts, Koichiro Kase, Mitsuyoshi Katayama, Takashi Ishihara, Hiroki Yamanaka, John T. Gupton Jan 1997

Efficient And General Synthesis Of Novel Β-Polyfluoroalkoxy Vinamidinium Salts, Koichiro Kase, Mitsuyoshi Katayama, Takashi Ishihara, Hiroki Yamanaka, John T. Gupton

Chemistry Faculty Publications

Novel β-polyfluoroalkoxy vinamidinium salts 3 and/or 4 were synthesized in good yields by the reaction of N-(2- polyfluoroalkoxy-3 ,3-difluoro-1-propenyI)trimethylammonium iodides (2), prepared from N-(2,3,3-trifluoro-1-propenyl)trimethylammonium iodide (1), with secondary amines in MeCN at 70 °C for 1 h. The salts were also obtainable in comparable yields by the one-pot reaction of 1 with sodium polyfluoroalkoxide followed by treatment with amines.

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Polymer Light Emitting Diodes, Frank E. Karasz, Bin Hu, Zhou Yang Jan 1997

Polymer Light Emitting Diodes, Frank E. Karasz, Bin Hu, Zhou Yang

Turkish Journal of Chemistry

Polyphenylene vinylene-based conjugated-nonconjugated alternating block copolymers form the active chromophores in a series of light emitting diodes (LEDs). The quantum efficiency and brightness of these devices can be improved by several orders of magnitude by incorporation of appropriate carrier transport layers and by rational choice of electrodes. Further improvements can be gained by blending of the active chromophores with high or low molecular weight species.

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Carbon Monoxide Hydrogenation Over Ru-Mn-K/Al_2o_3 Catalysts, S. Tajammul Hussain, M. Ashraf Atta Jan 1997

Carbon Monoxide Hydrogenation Over Ru-Mn-K/Al_2o_3 Catalysts, S. Tajammul Hussain, M. Ashraf Atta

Turkish Journal of Chemistry

The catalytic behavior of a series Ru/Al_2O_3 catalysts promoted with various levels of Mn and K prepared by coimpregnation were investigated in the CO-hydrogenation reaction. Catalytic studies showed that the addition of Mn enhances the production of Fischer Tropsch products and K promotion in particular enhances the production of unsaturated hydrocarbons while inhibiting the methanation reaction. The influence of K and Mn on the Fischer Tropsch product selectivity in CO-hydrogenation studies is discussed in terms of ensemble and electronic effects, and the production of a new surface site Ru:Mn:K.

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Ion Chromatographic Analysis Of Water-Soluble Anions In The Atmosphere In Amman, Jordan, Qasem M. Jaradat, Kamal A. Monami, Anwar G. Jiries Jan 1997

Ion Chromatographic Analysis Of Water-Soluble Anions In The Atmosphere In Amman, Jordan, Qasem M. Jaradat, Kamal A. Monami, Anwar G. Jiries

Turkish Journal of Chemistry

In the summer of 1995, samples of airborne particles were collected in the Amman area of Jordan. Ion chromatography (IC) was used for the determination of anions in these samples. Four anions were identified and quantified in the atmosphere of Amman. The concentration ranges of F^-, CL^-, NO_3^- and SO_4^= were 0.04 - 3.3, 2.25 - 15.7, 1.96 - 8.39 and 16.88 - 41.33 \mug/m^3, respectively. The study shows that Cl^-, NO_3^-, and SO_4^= are the major anions of air particulate, and the concentration of SO_4^= exceeds that of some other cities worldwide. The total suspended particles (TSP) value was …

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Epr Spectroscopy Of Dog-Rose Polyphenoloxidase, Çiğdem Nuhoğlu, Fatih Ucun, Enise Ayyildiz, Y. Kemal Yoğurtçu, Halis Şaki̇roğlu, İrfan Küfrevi̇oğlu Jan 1997

Epr Spectroscopy Of Dog-Rose Polyphenoloxidase, Çiğdem Nuhoğlu, Fatih Ucun, Enise Ayyildiz, Y. Kemal Yoğurtçu, Halis Şaki̇roğlu, İrfan Küfrevi̇oğlu

Turkish Journal of Chemistry

Polyphenoloxidase(PPO) of dog-rose fruit was extracted and purified through (NH\4)\2SO\4 precipitation and dialysis. The optimum conditions for this purpose, i.e., pH and temperature, were determined with 4-methylcatechol optimum pH and temperature and found to be pH 8.5 and 20\ci, respectively. The inhibition effect of ascorbic acid was investigated and the I_{50} value was found to be 1.57\times10^{-4} M. The activity of dog-rose PPO was investigated by electron paramagnetic resonance (EPR) at different pH levels and temperatures. The optimum conditions obtained from both spectrophotometry and EPR were compared.

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Catalytically Active Intermediates In Photochemical Metathesis, Çetin Bozkurt, Yavuz İmamoğlu Jan 1997

Catalytically Active Intermediates In Photochemical Metathesis, Çetin Bozkurt, Yavuz İmamoğlu

Turkish Journal of Chemistry

The nature of the active species in photocatalytic metathesis reaction was investigated. The formation of Wittig-type addition products with benzaldehyde indicates that catalytically active carbene is the product of olefin and tungsten hexacarbonyl under reaction conditions.

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Synthesis Characterization And Miscibility Of Polyvinyl Butyrals Of Varying Vinyl Alcohol Contents, Z. M. Zhou, D. J. David, W. J. Macknight, F. E. Karasz Jan 1997

Synthesis Characterization And Miscibility Of Polyvinyl Butyrals Of Varying Vinyl Alcohol Contents, Z. M. Zhou, D. J. David, W. J. Macknight, F. E. Karasz

Turkish Journal of Chemistry

Polyvinyl butyrals (PVB) of systematically varying vinyl alcohol content have been synthesized and characterized using wet chemistry, IR, DSC, and TGA. The miscibility of PVB-PVB blends was studied by DSC as a function of vinyl alcohol content and vinyl alcohol content differences between the respective blend components. These data were use to construct an isothermal miscibility map of PVB and to calculate the intramolecular interaction parameter \chi_{VA,VB}. The \chi_{VA,VB} was a function of the absolute level of the vinyl alcohol (VA) and vinyl butyral (VB) contents of the polymers. In addition, the thermal stability of polyvinyl butyral was found to …

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Suprachiasmatic Nucleus Neurons Are Glucose Sensitive, Adam C. Hall, Roselle M. Hoffmaster, Edra L. Stern, Mary E. Harrington, David Bickar Jan 1997

Suprachiasmatic Nucleus Neurons Are Glucose Sensitive, Adam C. Hall, Roselle M. Hoffmaster, Edra L. Stern, Mary E. Harrington, David Bickar

Chemistry: Faculty Publications

The suprachiasmatic nucleus (SCN) in the hypothalamus serves as the pacemaker for mammalian circadian rhythms. In a hamster brain slice preparation, the authors were able to record spontaneous activity from SCN cells for up to 4 days in vitro and verify a self-sustained rhythm in firing. The phase of this rhythm was altered by the concentration of glucose in the bathing medium, with time of peak firing advanced for a 20 mM glucose condition and slightly delayed for a 5 mM glucose condition, relative to 10 mM. The advancing effect of 20 mM glucose and the delaying effect of 5 …

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Network Characterization Of Energetic Poly(Glycidyl-Azide), Mehmet S. Eroğlu, Olgun Güven Jan 1997

Network Characterization Of Energetic Poly(Glycidyl-Azide), Mehmet S. Eroğlu, Olgun Güven

Turkish Journal of Chemistry

Energetic poly(glycidyl azide) (PGA) elastomers with different crosslink densities were prepared by varying the NCO/OH reactive-groups ratio from 0.8 to 1.0. In the preparation of the elastomers, PGA chains were end-liked with a mixture of hexamethylene diisocyanate (HMDI) and trimethylol propane (TMP) at a fixed TMP/PGA mole ratio. The number average molar mass between junction points of the network chains \overline{{\rm M}}_c was calculated using data obtained from swelling and uniaxial tensile tests and the results were compared. For the mechanical characterization of the networks, Mooney-Rivlin plots were prepared and the values of the constants 2C_1 and 2C_2 of PGA …

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Electrical Conductivity Of Sodium Doped Poly(4-Vinylpyridine), Murat Özyalçin, Zuhal Küçükyavuz, Aref Jarvaherian, Savaş Küçükyavuz Jan 1997

Electrical Conductivity Of Sodium Doped Poly(4-Vinylpyridine), Murat Özyalçin, Zuhal Küçükyavuz, Aref Jarvaherian, Savaş Küçükyavuz

Turkish Journal of Chemistry

Poly(4-Vinylpyridine) was synthesized by free radicalic polymerization. Solution doping process with metallic sodium was carried out. A conductivity value around 10^{-6} S/cm was obtained. Relative change in the coductivity with dopant concentration, temperature dependence of conductivity, conductivity behavior in atmospheric conditions for the samples were analyzed. SEM and EDX techniques were also used for the characterization of the polymer.

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Possible Roles Of Transition Metals In Cloudwater Relative To The Solar Short-Wave Radiation Absorption Anomaly, Xudong Huang, S. Sinan Keski̇n, Francis Pink, İlhan Ölmez Jan 1997

Possible Roles Of Transition Metals In Cloudwater Relative To The Solar Short-Wave Radiation Absorption Anomaly, Xudong Huang, S. Sinan Keski̇n, Francis Pink, İlhan Ölmez

Turkish Journal of Chemistry

Measurements of the absorption of solar short-wave radiation by clouds exceed those predicted by theoretical calculations. In order to understand the roles of minor and trace species in this absorption anomaly, cloudwater samples were collected from individual precipitating clouds and analyzed for trace metals and anionic species. Two generalized approaches were used to assess the direct impact of the absorption of solar short-wave radiation by transition metals and/or their anionic complexes. Additionally, it was suggested that iron and manganese may act as catalyts in the formation of sulfate aerosols which efficiently scatter solar radiation.

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Synthesis And Characterization Of Complexes Of Co(Ii), Ni(Ii), Cd(Ii), Hg(Ii) And Pd(Ii) With Some N-Phenyl-N^{1}-2-[4-Phenyl-(Substituted) Thiazolyl]- Thioureas, B. Narayana, M. R. Gajendragad Jan 1997

Synthesis And Characterization Of Complexes Of Co(Ii), Ni(Ii), Cd(Ii), Hg(Ii) And Pd(Ii) With Some N-Phenyl-N^{1}-2-[4-Phenyl-(Substituted) Thiazolyl]- Thioureas, B. Narayana, M. R. Gajendragad

Turkish Journal of Chemistry

The Synthesis and characterization of the complexes of Co(II), Ni(II), Pd(II), Cd(II) and Hg(II) with N-phenyl-N^{1}-2(-4-phenylthiazoly)thiourea (PPT) and N-phenyl-N^{1}-2-(4-methylphenylthiazolyl)-thiourea (PMPT) and Co(II), Cd(II), and Hg(II) complexes of N-phenyl-N^{1}-2-(4-p- chlorophenylthiazolyl) thiourea (PCPT) are included in this paper. Based on analytical results, electronic and infrared spectral data and magnetic susceptibility measurements, plausible structures have been proposed.

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Reduction Of Combustion Generated Pollution: Process Modifications And Energy Efficient Power Cycles, Janos M. Beer Jan 1997

Reduction Of Combustion Generated Pollution: Process Modifications And Energy Efficient Power Cycles, Janos M. Beer

Turkish Journal of Chemistry

Theoretical bases of combustion process modifications aimed at the reduction of pollutant emission are examined. It is shown, as an example, of how the minimization of emissions of nitrogen oxides leads to a design protocol that translates results of modeling and of bench scale experiments into guidelines for industrial design. The formation and emission of polycyclic aromatic compounds is also considered, because their formation is strongly favored in "low NO_x flames". In power generation the pollutant emission can be reduced effectively by the improvement of the ``heat rate,"i.e., the thermodynamic efficiency of the power cycle. Combined gas turbine-steam cycles which …

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Examination Of Historical Textiles With Dyestuff Analyses By Tlc And Derivative Spectrophotometry, Recep Karadağ, Emre Dölen Jan 1997

Examination Of Historical Textiles With Dyestuff Analyses By Tlc And Derivative Spectrophotometry, Recep Karadağ, Emre Dölen

Turkish Journal of Chemistry

A group of historical textiles in the Topkapi Museum, i.e., silk brocades classified as 16th century pieces by art historians, were investigated by TLC and spectrophometric analyses of their dyestuffs for the purpose of dating these pieces. The dyestuffs contained intextile fibers were extracted with acid solutions of varying strength, and the acid extracts were analyzed by both TLC and spectrophotometry, either directly or after an organic solvent extraction step. The first derivative spectra proved to provide more information than the main spectra. In order to eliminate possible interferences in spectrophotometry arising from impurities in the fibers, e.g., compounds containing …

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Investigation Of Hmo Spectra Of Hückel And Mobius Type Cyclacenes, Lemi Türker, Şakir Erkoç Jan 1997

Investigation Of Hmo Spectra Of Hückel And Mobius Type Cyclacenes, Lemi Türker, Şakir Erkoç

Turkish Journal of Chemistry

The Hückel molecular orbital spectra (HMO) of Hückel- and Mobius-type cyclacenes having 3-15 benzenoid rings were investigated and it was found that certain eigenvalues are topologically invariant, whereas others exhibit topological periodicity. For example, Hückel-type cyclacenes having 2r (r: 2,3,4,...) benzenoid rings which possess nonbonding molecular orbitals (NBMO) and are thus expected to be open shell structures.

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Apocarbonic Anhydrase-Enzymatic Determination Of Zinc In Fruit Juices, Ayşe Karagölge, Nazan Demi̇r, Yaşar Demi̇r, İrfan Küfrevi̇oğlu Jan 1997

Apocarbonic Anhydrase-Enzymatic Determination Of Zinc In Fruit Juices, Ayşe Karagölge, Nazan Demi̇r, Yaşar Demi̇r, İrfan Küfrevi̇oğlu

Turkish Journal of Chemistry

In this study, a new enzymatic method for determining trace amount of zinc was employed on ten different fruit juices. The basis of the enzymatic method is that apocarbonic anhydrase regains its activity in proportion to the Zn^{2+} existing in a solution. Thus, the more activated the enzyme is in the medium, the higher the Zn^{2+} concentration in the solution will be. For this purpose, bovine carbonic anhydrase was purified from erythrocyte hemolisate by affinity chromatography. The Zn^{2+} bound to the enzyme was removed by of the purified enzyme against the solution of pyridine-2-6-dicarboxylic acid. Thus 100\% purified enzyme was …

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Some Oxidation Reactions Of Isomeric Pyridinecarboxylic Acid Hydrazides, Rashid Iqbal, Samia Ebrahim, Muhammad Ziaulhaq Jan 1997

Some Oxidation Reactions Of Isomeric Pyridinecarboxylic Acid Hydrazides, Rashid Iqbal, Samia Ebrahim, Muhammad Ziaulhaq

Turkish Journal of Chemistry

The oxidation reactions of the three isomeric pyridinecarboxylic acid hydrazides were studied using sodium metaperidoate, silver(I) oxide and potassium ferricyanide separately. Potassium ferricyanide emerged as an excellent reagent for preparation of 2-pyridinecarboxaldehyde and 3-pyridinecarboxaldehyde from the respective isomeric pyridinecarboxylic acid hydrazides. Oxidation with silver(I) oxide in each case yielded the corresponding 1,2-dipyridoylhydrazine, while sodium metaperiodate furnished different products with each isomeric pyridinecarboxylic acid hyrazide.

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^1h Nmr, Infrared And Mass Spectrometry Of Di- And Tri-Organotin Derivatives Of 1-Nitroso-2-Naphthol, Saqib Ali, Muhammad Mazhar, Moazzam Hussain Bhatti, Sohail Mahmood, Abida Kalsoom Jan 1997

^1h Nmr, Infrared And Mass Spectrometry Of Di- And Tri-Organotin Derivatives Of 1-Nitroso-2-Naphthol, Saqib Ali, Muhammad Mazhar, Moazzam Hussain Bhatti, Sohail Mahmood, Abida Kalsoom

Turkish Journal of Chemistry

The di- and tri-organotin derivatives R\2SnL\2 and R\3SnL where R = CH\3, n--C\4H\9, C\6H\5, C\6H_{11} and C\6H\5CH\2 and L = 1-nitroso-2-naphthoxy were synthesized. These derivatives were characterized by elemental analysis, infrared, ^1H NMR and mass spectrometry.

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Solvent Impregnated Resins For The Recovery Of Gold From Gold(I)Thiourea Solutions, Fiona Fitzpatrick Jan 1997

Solvent Impregnated Resins For The Recovery Of Gold From Gold(I)Thiourea Solutions, Fiona Fitzpatrick

Masters

Solvent Impregnated Resins (SIRs) are high surface area, macroporous, polymeric resins which have been physically impregnated with an organic solvent. In this research, three resins have been impregnated with Di-2-ethylhexyl phosphoric acid, a solvent which has shown selectivity to gold. The ability of the resins to recover gold (1) thiourea perchlorate from solution has been investigated. The resins have been studied both bare and when impregnated with the solvent and their efficiency was seen to increase upon impregnation. The overall efficiency of the resins was found to be pH dependent. It is also related to the level of impregnation of …

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Dichlorobis[1,3-Dimethylimidazole-2(3h)-Selone-Se]Cobalt(Ii), Daniel J. Williams, Timothy Jones, Edward D. Rice, Kerri J. Davis, John A. Ritchie, William T. Pennington, George L. Schimek Jan 1997

Dichlorobis[1,3-Dimethylimidazole-2(3h)-Selone-Se]Cobalt(Ii), Daniel J. Williams, Timothy Jones, Edward D. Rice, Kerri J. Davis, John A. Ritchie, William T. Pennington, George L. Schimek

Faculty Articles

The crystal structure of the title compound, [CoCl2(C5H8N2Se)2], shows a discrete molecular structure with tetrahedral geometry around the cobalt ion. The mean Co-Cl and Co-Se distances are 2.277 (3) and 2.456 (3) Å, respectively. Bond angles around the Co atom range from 101.1 (1) to 120.0 (1)°. Ring distances and angles in the ligand compare favorably with the literature values of analogous compounds, and show significant increases from values observed in the uncoordinated selone. However, the mean C-Se bond distance of 1.88 (2) Å shows no significant difference from the …

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