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Articles 26101 - 26130 of 34739

Full-Text Articles in Physical Sciences and Mathematics

Investigation Of The Structure In Electrodeposited Nanostructured Co/Cu Alloys, Multilayers, And Cofe/Cu Multilayered Nanowires, Erick Jamal Lawson Jan 2006

Investigation Of The Structure In Electrodeposited Nanostructured Co/Cu Alloys, Multilayers, And Cofe/Cu Multilayered Nanowires, Erick Jamal Lawson

LSU Master's Theses

Since the discovery of giant magnetoresistance (GMR) in electrodeposited nanostructured magnetic multilayers and multilayered nanowires, there has been interest throughout the scientific world in the fabrication and characterization of these materials. Magnetic multilayers in the form of thin films can be used as magnetoresistive sensors in the magnetic data storage industry. Arrays of nanowires have the potential for applications in perpendicular ultra-high density data storage and biosensors. Wire-shaped magnetic multilayered nanowires have been shown to exhibit GMR in the so called “current perpendicular-to plane” configuration (CPP-GMR). GMR of multilayers and multilayered nanowires have been investigated in several systems that include …

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Mcd And Magnetization Studies On Nifb/Nifz Minus Molybdenum Iron Protein From Azotobacter Vinelandii, Marcia S. Cotton Jan 2006

Mcd And Magnetization Studies On Nifb/Nifz Minus Molybdenum Iron Protein From Azotobacter Vinelandii, Marcia S. Cotton

LSU Master's Theses

This study reports a characterization of the iron-sulfur clusters of the MoFe protein expressed by the nifBnifZ deletion strain of A. vinelandii. VT-MCD spectroscopic and magnetization analysis of as-isolated ΔnifBΔnifZ MoFe protein were undertaken. VT-MCD spectra of as-isolated ΔnifBΔnifZ MoFe protein contains bands remarkably similar to those seen in as-isolated ΔnifH MoFe protein, assigned to arise from an [4Fe-4S]+ cluster. The low-temperature magnetization curve of as-isolated ΔnifBΔnifZ MoFe protein reveals the MCD spectra bands stem from an S = ½ spin system with diamagnetic contributions of some other species. As-isolated ΔnifBΔnifZ MoFe protein is compared with as-isolated ΔnifH MoFe …

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Uv Cure Kinetics Of Dimethacrylate Thin And Thick Samples, Yuemei Zhang Jan 2006

Uv Cure Kinetics Of Dimethacrylate Thin And Thick Samples, Yuemei Zhang

Dissertations, Theses, and Masters Projects

UV curing is using UV light as the energy source to induce the polymerization of liquid monomers and oligomers to form a solid polymer. Because UV polymerization is fast and energy-saving and a UV curable system has no VOC (volatile organic compound), this new technology has developed rapidly from thin film applications to thick sample applications. In addition, since the UV cure process can be controlled spatially and temporally, it also has an important application to make gradient materials with locally optimized properties. However, most research on UV cure is based on thin film applications, and the cure kinetics of …

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Ab Initio Molecular Dynamics Simulations Of Methylaluminoxane (Mao) Synthesis By Hydrolysis Of Trimethylaluminum, Lacramioara Negureanu Jan 2006

Ab Initio Molecular Dynamics Simulations Of Methylaluminoxane (Mao) Synthesis By Hydrolysis Of Trimethylaluminum, Lacramioara Negureanu

LSU Doctoral Dissertations

MAO is the co-catalyst in the metallocene catalytic systems, which are widely used in single site olefin polymerization due to their high stereoselectivity. To date, the precise structure of MAO, the particular compound or compounds catalytically active in MAO, have eluded researchers. MAO, a white amorphous powder, is not a good sample for a direct spectroscopic characterization, and its NMR spectra are broad and almost featureless. Many structural models have been proposed but none are generally accepted. In the first part of this work the MAO formation mechanism was addressed. Molecular dynamics simulations at MP2 configuration interaction theory level have …

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Investigation Into The Dirhodium-Catalyzed Hydroformylation Of 1-Alkenes And Preparation Of A Novel Tetraphosphine Ligand, Alexandre R. Monteil Jan 2006

Investigation Into The Dirhodium-Catalyzed Hydroformylation Of 1-Alkenes And Preparation Of A Novel Tetraphosphine Ligand, Alexandre R. Monteil

LSU Doctoral Dissertations

The reaction of the tetraphosphine ligand rac-et,ph-P4 (et,ph-P4 = PEt2CH2CH2(Ph)PCH2P(Ph)CH2CH2PEt2) with 2 equiv. of [Rh(nbd)2]+ (nbd = norbornadiene) generates [rac-Rh2(nbd)2(et,ph-P4)]2+, which is the precursor to a highly active and regioselective hydroformylation catalyst system. The “key” catalyst species generated under H2/CO pressure has been proposed to be the dihydrido complex [rac-Rh2H2(ì-CO)2(et,ph-P4)]2+, and represents one of the most dramatic example of homobimetallic …

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Simulating Protein Evolution Via Thermodynamic Models, Yanlong Xu Jan 2006

Simulating Protein Evolution Via Thermodynamic Models, Yanlong Xu

LSU Doctoral Dissertations

Natural proteins are results of evolution and they need to maintain certain thermodynamic stabilities in order to carry out their biological functions. By simulating protein evolution based on thermodynamic rules, we could reconstruct the evolution trajectory and analyze the evolutionary dynamics of a protein population, and further understand the protein sequence-structure-function relationship. In this study, we have used both a simplified lattice model and a high-resolution atomic model to simulate protein evolution processes. With the lattice model, we have investigated general theoretical questions about how protein structural designability would affect protein evolution, particularly how it would affect protein recombination and …

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Influence Of Surface Chemistry On The Aggregation Of Beta Amyloid Peptide, Mariah Joan Wooldridge Mcmasters Jan 2006

Influence Of Surface Chemistry On The Aggregation Of Beta Amyloid Peptide, Mariah Joan Wooldridge Mcmasters

LSU Doctoral Dissertations

Alzheimer's disease is a progressive neurological ailment affecting 4.5 million aging Americans. The disease is characterized by the presence in the brain of self-assembled fibrils consisting of beta amyloid protein (Aβ). Soluble Aβ protein is present in normal human cerebrospinal fluid, but it is unclear what makes the protein aggregate into insoluble plaques. There is evidence that the Aβ fibril assembly is affected by interactions with biological surfaces, such as neuronal membranes. Here, surfaces consisting of self-assembled alkanethiol monolayers with different end groups were used to test the effect of surface chemistry on the structure and morphology of aggregates formed …

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Characterization Of Beta-Amyloid Peptide Aggregation And Acceleration With Non-Fibrillar Forming Peptide-Based Mediators, Nadia J. Edwin Jan 2006

Characterization Of Beta-Amyloid Peptide Aggregation And Acceleration With Non-Fibrillar Forming Peptide-Based Mediators, Nadia J. Edwin

LSU Doctoral Dissertations

Protein aggregation occurs under many circumstances, from the dynamic assembly of tubulin to form microtubules, the aggregation of actin into filaments, as well as plaque formation by amyloid precipitation. One important requirement in studying the mechanism of amyloid aggregation is the ability to monitor the growth kinetics over a wide range in size scales (10 nm to microns) with time that spans microseconds to seconds. Understanding the mechanisms of the aggregation may then lead to improved design of drugs to help control or suppress the aggregation process. In this dissertation, the physical characterization of the â-amyloid peptide and its interaction …

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Synthesis, Characterization And Properties Of Cooper(Ii) Beta-Diketonate Macrocycles, Sylvester Burton Jan 2006

Synthesis, Characterization And Properties Of Cooper(Ii) Beta-Diketonate Macrocycles, Sylvester Burton

LSU Doctoral Dissertations

This dissertation deals with the synthesis and properties of multidentate β-diketone ligands and their transition-metal complexes. (1) We prepared two bis(β-diketones), C1BAH2 and p-XBAH2 (see sketch below), determined their crystal structures, and studied their reactions with copper(II). We envisioned that they would form macrocyclic complexes with 3-6 metal atoms. In both cases, although the initial products are soluble, as expected for the desired molecular products, we were unable to isolate well-behaved molecular solids. In the case of C1BAH2, this may be because the cyclic product requires an unusual combination of conformations of …

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Self-Assembly And Its Inhibition In Bolaform Amphiphilic Dendrimers, Jirun Sun Jan 2006

Self-Assembly And Its Inhibition In Bolaform Amphiphilic Dendrimers, Jirun Sun

LSU Doctoral Dissertations

Self-assembly is scientifically interesting, technologically important, and sometimes life-threatening. A striking example: Alzheimer’s disease is caused by the self-assembly of the â-amyloid fragment of amyloid precursor protein. Such natural amphiphiles normally are very expensive and complicated to isolate. Synthetic mimics that are much cheaper and easier to prepare can facilitate the development of efficient characterization methods, even as they suggest new materials science applications. Two-directional arborols are synthetic bolaform amphiphilic dendrimers. They dissolve in hot water and form reversible gels at room temperature. Bundles of fibrils, which are made by self-assembly of arborols, are found in the gels. The properties …

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Applications Of Titanium-Mediated Reductive Coupling And Cyclocarbonylation Reactions Toward Natural Product Synthesis, Maria A. Appeaning Jan 2006

Applications Of Titanium-Mediated Reductive Coupling And Cyclocarbonylation Reactions Toward Natural Product Synthesis, Maria A. Appeaning

LSU Doctoral Dissertations

Previous work in our laboratory has demonstrated not only a synthetic value of tandem reductive cyclization - carbonylation reactions in the preparation of complex molecules but also the interesting stereoselectivity observed therein. The first part of this work employs the titanium-mediated cyclocarbonylation of tethered dienals for the synthesis of prostaglandin analogues, in particular PGF2α and methyl jasmonate. Based on this hetero Pauson-Khand strategy, we have established an efficient racemic route to both the prostaglandin and the methyl jasmonate core skeletons. Moderate to excellent selectivities with regard to the hetero Pauson-Khand reaction were observed in both cases. The second part …

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Growth Of Ge Quantum Dots On Si(100)-(2×1) By Pulsed Laser Deposition, M. S. Hegazy, H. E. Elsayed-Ali Jan 2006

Growth Of Ge Quantum Dots On Si(100)-(2×1) By Pulsed Laser Deposition, M. S. Hegazy, H. E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Self-assembled germanium quantum dots (QDs) were grown on Si(100)-(2×1) by pulsed laser deposition. In situ reflection-high energy electron diffraction (RHEED) and postdeposition atomic force microscopy are used to study the growth of the QDs. Several films of different thicknesses were grown at a substrate temperature of 400 °C using a Q-switched Nd:yttrium aluminum garnet laser (λ= 1064 nm, 40 ns pulse width, 23 J/cm 2 fluence, and 10 Hz repetition rate). At low film thicknesses, hut clusters that are faceted by different planes, depending on their height, are observed after the completion of the wetting layer. With increasing film thickness, …

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A Prelude To A Third Dimension Of The Periodic Table: Superatoms Of Aluminum Iodide Clusters, Naiche Owen Jones Jan 2006

A Prelude To A Third Dimension Of The Periodic Table: Superatoms Of Aluminum Iodide Clusters, Naiche Owen Jones

Theses and Dissertations

Calculations have been carried out to investigate the stability and electronic structure of aluminum iodide clusters using first principles gradient-corrected density functional theory. Analysis of A113Ix-, A114Ix-, and A17I- clusters reveals that their stability is governed by the geometrically unperturbed A113-, A1142+, and A17+ units, respectively, that are demonstrated to constitute the compact cores of the clusters upon significant iodine content. The compact, icosahedral A113, icosahedral-like A1 14, and capped square bi-pyramid A17 superatom structures of the stable aluminum cores have an analogous electronic configuration to that of halogen, alkaline-earth, and alkaline atoms, respectively. Novel chemistry is demonstrated in superatoms, …

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Quantitative Model For The Prediction Of Hydrodynamic Size Of Nonionic Reverse Micelles, Melissa A. Michaels Jan 2006

Quantitative Model For The Prediction Of Hydrodynamic Size Of Nonionic Reverse Micelles, Melissa A. Michaels

Theses and Dissertations

The sizes of nonionic reverse micelles were investigated as a function of the molecular structure of the surfactant, the type of oil, the total concentration of surfactant [NP], the ratio of NP4 to total surfactant (r), the water to surfactant molar ratio (ω), temperature, salt concentration, and polar phase. The basis of our investigation was nonylphenol polyethoxylates - NP4 and NP7. Micelle sizes were determined using dynamic light scattering (DLS). A central composite experimental design was used to quantitatively model reverse micelle size as a function of ω, [NP], and r. The model has demonstrated the capability of predicting the …

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Photochemical Applications To The Study Of Complexity Phospholipid Bilayer Environments, Christopher John Wohl Jr. Jan 2006

Photochemical Applications To The Study Of Complexity Phospholipid Bilayer Environments, Christopher John Wohl Jr.

Theses and Dissertations

The physical and biophysical properties of a biological membrane model, phosphatidylcholine bilayers, were investigated using novel spiropyran/merocyanine molecular probes. The femtosecond to second dynamics of this system's photochemistry enabled bilayer viscosity and free volume to be studied over a broad time scale. Spiropyrans/merocyanines with different polarity were synthesized by changing the substitution of the indole moiety enabling determination of the trans-membrane properties of the bilayer. In addition, transient grating spectroscopy was used to study thermal energy transfer in phospholipid bilayers on a picosecond time scale.Femtosecond transient absorption spectroscopy was used to study the photo-induced spiropyran ring-opening and isomerization reactions that …

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Simultaneous Ejection Of Six Electrons At A Constant Potential By Hexakis(4-Ferrocenylphenyl)Benzene, Vincent J. Chebny, Dwairath Dhar, Sergey V. Lindeman, Rajendra Rathore Jan 2006

Simultaneous Ejection Of Six Electrons At A Constant Potential By Hexakis(4-Ferrocenylphenyl)Benzene, Vincent J. Chebny, Dwairath Dhar, Sergey V. Lindeman, Rajendra Rathore

Chemistry Faculty Research and Publications

A simple synthesis of a dendritic hexaferrocenyl electron donor (5) is described in which six ferrocene moieties are connected at the vertices of the propeller of the hexaphenylbenzene core. The molecular structure of 5 is confirmed by X-ray crystallography. An electrochemical analysis along with redox titrations (which are tantamount to coulometry) confirmed that it ejects six electrons at a single potential.

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Thermal And Flame Properties Of Polyethylene And Polypropylene Nanocomposites Based On An Oligomerically–Modified Clay, Jinguo Zhang, David D. Jiang, Charles A. Wilkie Jan 2006

Thermal And Flame Properties Of Polyethylene And Polypropylene Nanocomposites Based On An Oligomerically–Modified Clay, Jinguo Zhang, David D. Jiang, Charles A. Wilkie

Chemistry Faculty Research and Publications

An oligomerically-modified clay was made using a surfactant which is the ammonium salt of an oligomer. The newly modified clay contains 37.5% inorganic clay and 62.5% oligomer. Polyethylene and polypropylene nanocomposites were made by melt blending the polymer with the oligomerically-modified clay in a Brabender mixer at various clay loadings. The structure of the nanocomposites was characterized by X-ray diffraction and transmission electron microscopy. Mechanical testing showed that the polyethylene nanocomposites had an enhanced Young's modulus and slightly decreased elongation, while the changes for polypropylene nanocomposites are small compared with the virgin polymers. The thermal stability and flame properties were …

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Analysis Of Nanoparticle Transmission Electron Microscopy Data Using A Public- Domain Image-Processing Program, Image, Gerd H. Woehrle, James E. Hutchison, Sai̇m Özkar, Richad G. Finke Jan 2006

Analysis Of Nanoparticle Transmission Electron Microscopy Data Using A Public- Domain Image-Processing Program, Image, Gerd H. Woehrle, James E. Hutchison, Sai̇m Özkar, Richad G. Finke

Turkish Journal of Chemistry

The need to easily and quickly count larger numbers of nanoparticles, in order to obtain statistically useful size and size-distribution data, is addressed via the use of a readily available, free, public-domain program for particle counting, NIH-Image (and 2 others derived from it, Scion Image and Image J), collectively referred to herein as Image. The best protocols that we have found useful for the use of Image are reported; both appropriate as well as problematic applications of Image are then illustrated with a series of TEM images of Ir(0), Pd(0) and Au(0) nanoclusters. Methods to detect and image nanoclusters with …

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Phytochemical Studies On The Underground Parts Of Asperula Taurina Subsp. Caucasica, Ufuk Özgen, Cavi̇t Kazaz, Hasan Seçen, Maksut Coşkun Jan 2006

Phytochemical Studies On The Underground Parts Of Asperula Taurina Subsp. Caucasica, Ufuk Özgen, Cavi̇t Kazaz, Hasan Seçen, Maksut Coşkun

Turkish Journal of Chemistry

One naphthohydroquinone (mollugin) (1), 3 anthraquinones (1-hydroxy-2-methyl-9,10-anthraqinone (2), 1,3-dihydroxy-2-methoxymethyl- 9,10-anthraquinone (4) and 1,3-dihydroxy-2-carboxy-9,10-anthraquinone (7, munjistin)), \beta-sitosterol (3), 1 naphthalene glycoside (2-carbomethoxy-3-prenyl-1,4-naphtho-hydroquinone, 1,4-di-O-\beta -glucoside (5)) and 1 anthraquinone glycoside (lucidin-3-O-\beta -primeveroside (6)) were isolated from the underground parts of A. taurina subsp. caucasica. The structures of the isolates were established by MS, ^1H-NMR and ^{13}C-NMR analysis.

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Cyclic Triterpenoid Saponins From Campanula Lactiflora, Nuretti̇n Yayli, Asu Usta, Ahmet Yaşar, Osman Üçüncü, Canan Güleç, Mustafa Küçükislamoğlu Jan 2006

Cyclic Triterpenoid Saponins From Campanula Lactiflora, Nuretti̇n Yayli, Asu Usta, Ahmet Yaşar, Osman Üçüncü, Canan Güleç, Mustafa Küçükislamoğlu

Turkish Journal of Chemistry

Two cyclic natural compounds, 3\beta-O-[\alpha-L-rhamnopyranosyl- (1 \to 2)-\beta-D-glucopyranosyl]-13\alpha,14\alpha-epoxy-8\alpha,12\beta, 15-trihydroxy-(17E,21E)-17,21-campanuldien-6'(30)-olide, called lactifloroside A, 1, and 3\beta-O-[\beta-D-glucopyranosyl-(1 \to 2)-\beta-D-glucopyranosyl]- 13\alpha,14\alpha-epoxy-8\alpha,12\beta-dihydroxy-(17E,21E)-17,21-campanuldien- 6'(30)-olide, called lactifloroside B, 2, were isolated for the first time from Campanula lactiflora and their structures deduced by high field 1D and 2D 400 MHz NMR, FT-IR, HPLC, GC-MS, (+/-) LC-MS/MS and (+) FAB-MS spectra. The aglycones of the 2 saponins were named 13\alpha,14\alpha-epoxy-3\beta,8\alpha,12\beta,15-tetrahydroxy-(17E,21E)- 17,21-campanuldien-30-oic acid and 13\alpha,14\alpha-epoxy-3\beta,8\alpha, 12\beta-trihydroxy-(17E,21E)-17,21-campanuldien-30-oic acid, and designated as campanuloic acid and 15-deoxycampanuloic acid, respectively.

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Synthesis And Anticancer Evaluation Of Some New Unsymmetrical 3,5-Diaryl-4h-1,2,4-Triazole Derivatives, Olcay Beki̇rcan, Bahi̇tti̇n Kahveci̇, Murat Küçük Jan 2006

Synthesis And Anticancer Evaluation Of Some New Unsymmetrical 3,5-Diaryl-4h-1,2,4-Triazole Derivatives, Olcay Beki̇rcan, Bahi̇tti̇n Kahveci̇, Murat Küçük

Turkish Journal of Chemistry

A series of 4-arylidenamino-4H-1,2,4-triazole derivatives (3-11) were synthesized from the treatment of 4-amino-4H-1,2,4-triazoles (2) with certain aldehydes. Compounds 3-11 were reduced with NaBH_4 to afford the corresponding 4-arylmethylenamino-4H-1,2,4-triazoles (12-20). Compounds 1-10 and 12-19 were characterized by elemental analyses and ^1H NMR, ^{13}C NMR, IR and UV spectral data. Compounds 11 and 20 were characterized by ^1H NMR, ^{13}C NMR, IR and mass spectral data. Compounds 14, 16, 17, and 18 were tested for anticancer activities. Compound 17, chosen for its higher anticancer activity in the preliminary tests with the cancer cell lines of MCF7, NCI-H460, and SF-268, exhibited remarkable anticancer …

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Synthesis And Characterization Of Metal Complexes Of Cu(Ii), Ni(Ii), Zn(Ii), Co(Ii), Mn(Ii) And Cd(Ii) With Tetradentate Schiff Bases, Jianning Liu, Bo-Wan Wu, Bing Zhang, Yongchun Liu Jan 2006

Synthesis And Characterization Of Metal Complexes Of Cu(Ii), Ni(Ii), Zn(Ii), Co(Ii), Mn(Ii) And Cd(Ii) With Tetradentate Schiff Bases, Jianning Liu, Bo-Wan Wu, Bing Zhang, Yongchun Liu

Turkish Journal of Chemistry

4-(Benzeneazo)salicylaldehyde was synthesized with aniline, sodium nitrite and salicylaldehyde. Two tetradentate ligands, N,N'-bis[4-(benzeneazo) salicylaldehyde]-o-phenylenediamine (H_2L) and N,N'-bis[4-(benzeneazo) salicylaldehyde]ethylenediamine (H_2L') were formed by the 2:1 molar condensation of 4-(benzeneazo) salicylaldehyde with o-phenylenediamine or ethylenediamine. Their Cu(II), Ni(II), Zn(II), Co(II), Mn(II) and Cd(II) complexes were synthesized and characterized by elemental analysis, molar conductivity measurements, and infrared and electronic spectral data. Two ligands and their Ni(II) and Zn(II) complexes were further identified using ^1H NMR spectra. The results suggest that the metal is bonded to the ligand through the phenolic oxygen and the imino nitrogen.

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First- And Second-Derivative Spectrophotometry For Simultaneous Determination Of Copper And Cobalt By 1-(2-Pyridylazo)-2-Naphthol In Tween 80 Micellar Solutions, Habibollah Eskandari, Ali Ghanbari Saghseloo, Mansour Arab Chamjangali Jan 2006

First- And Second-Derivative Spectrophotometry For Simultaneous Determination Of Copper And Cobalt By 1-(2-Pyridylazo)-2-Naphthol In Tween 80 Micellar Solutions, Habibollah Eskandari, Ali Ghanbari Saghseloo, Mansour Arab Chamjangali

Turkish Journal of Chemistry

1-(2-Pyridylazo)-2-naphthol (PAN) has been used for the simultaneous determination of copper and cobalt at trace levels. PAN at pH 1.89 forms red and green complexes with copper and cobalt, respectively, which are soluble in aqueous Tween 80 micellar media and are stable for at least 3 days. Under optimum conditions, calibration graphs were obtained for individual determination of copper and cobalt by zero- and first-derivative spectrophotometry and for simultaneous determination by first- and second-derivative spectrophotometry. Zero-crossing first-derivative spectrophotometry at 555 and 581 nm for cobalt and copper was used for the simultaneous determination, respectively. The second derivative method at 577 …

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Kinetics And Mechanism Of Oxidation Of 1,3--Butylene Glycol By Dihydroxyditellutoargentate(Iii) In Alkaline Medium, Jin-Huan Shan, Shu-Ying Huo, Shi-Gang Shen, Han-Wen Sun Jan 2006

Kinetics And Mechanism Of Oxidation Of 1,3--Butylene Glycol By Dihydroxyditellutoargentate(Iii) In Alkaline Medium, Jin-Huan Shan, Shu-Ying Huo, Shi-Gang Shen, Han-Wen Sun

Turkish Journal of Chemistry

The kinetics of oxidation of 1,3--butlene glycol (\beta - BG) by dihydroxyditelluto- argentate(III) were studied spectrophotometrically between 298.2 and 313.2 K in alkaline medium. The reaction rate showed pseudo-first order dependence in oxidant and fractional order in \ss-BG. The pseudo-first order rate constant k_{obs} increased with an increase in the concentration of OH^- and a decrease in the concentration of TeO_4^{2-} . There was a negative salt effect and no free radicals were detected. Thus, the dihydroxymonotelluratoargentate(III) species is assumed to be the active species. The activation parameters along with the rate constants of the rate-determining step were calculated.

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Composition And Antimicrobial Activities Of Volatile Components Of Minuartia Meyeri, Nuretti̇n Yayli, Canan Güleç, Osman Üçüncü, Ahmet Yaşar, Serdar Ülker, Kami̇l Coşkunçelebi̇, Sali̇h Terzi̇oğlu Jan 2006

Composition And Antimicrobial Activities Of Volatile Components Of Minuartia Meyeri, Nuretti̇n Yayli, Canan Güleç, Osman Üçüncü, Ahmet Yaşar, Serdar Ülker, Kami̇l Coşkunçelebi̇, Sali̇h Terzi̇oğlu

Turkish Journal of Chemistry

The essential oil of air-dried Minuartia meyeri (Boiss.) Bornm. (Caryophyllaceae) was obtained by hydrodistillation in a Clevenger-type apparatus and analyzed by GC-MS. Fifty-two components were identified in the oil. The main components in the essential oil of M. meyeri were nonacosane (6.2%), 6,10,14-trimethyl-2-pentadecanone (5.1%), nonanal (4.6%), and beta-caryophyllene (2.9%). The antimicrobial activity of the isolated essential oil of the plant was also investigated and it showed moderate antibacterial activity against Gram-positive and Gram-negative bacteria, but no antifungal activity was observed against 2 yeast-like fungi.

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Chromium(Iii) Complexes With Different Chromospheres Macrocyclic Ligands: Synthesis And Spectroscopic Studies, Rajiv Kumar, Rajeev Singh Jan 2006

Chromium(Iii) Complexes With Different Chromospheres Macrocyclic Ligands: Synthesis And Spectroscopic Studies, Rajiv Kumar, Rajeev Singh

Turkish Journal of Chemistry

Symmetric tetradentate (L^1) and asymmetric pentadentate (L^2) macrocyclic ligands that possess 2 dissimilar coordination sites were prepared. One has a 4-coordinate (N_4) and the other has a 5-coordinate (N_2O_3S) donor set. Trivalent Cr(III) complexes were synthesized with L^1 and L^2 and their structures were investigated using elemental analyses and magnetic moment, electronic, IR, ^1H NMR, ^{13}C NMR and EPR spectra. All the Cr(III) complexes show magnetic moments corresponding to a high-spin configuration. \Delta values indicate the energy difference between the principle bands, which are formed due to ligand field absorption. The spin-orbit coupling parameter, z, gives no significance because the …

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A Novel Alkaloid From Stapelia Hirsuta, Marwan Shabana, Mariam Gonaid, Maha Mahmoud Salama, Essam Abdel-Sattar Jan 2006

A Novel Alkaloid From Stapelia Hirsuta, Marwan Shabana, Mariam Gonaid, Maha Mahmoud Salama, Essam Abdel-Sattar

Turkish Journal of Chemistry

A novel alkaloid (1,8,8-trimethyl-5,8-dihydro-1H-pyrano[3,4-b]pyridine-4,6-dione) was isolated from the chloroformic traction obtained from the total alcoholic extract of the aerial parts of Stapelia hirsuta L. In addition, apigenin, luteolin and \beta-sitosterol-3-O-\beta-D- glucopyranoside were also isolated.

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Synthesis Of A Ruthenium Complex Bound To A Polyimide Matrix: Investigating The Catalytic Properties In A Hydrosilylation Reaction, Turgay Seçki̇n, Süleyman Köytepe, İsmai̇l Özdemi̇r, Beki̇r Çeti̇nkaya Jan 2006

Synthesis Of A Ruthenium Complex Bound To A Polyimide Matrix: Investigating The Catalytic Properties In A Hydrosilylation Reaction, Turgay Seçki̇n, Süleyman Köytepe, İsmai̇l Özdemi̇r, Beki̇r Çeti̇nkaya

Turkish Journal of Chemistry

3,6-Bis(dimethylamino)acridine(hexamethylbenzene)dichlororuthenium(II) was used as a tricyclic heteroatomic monomer to prepare polyimides from the corresponding dianhyrides by solution condensation. The ruthenium complex monomer was synthesized starting from [RuCl_2(HMB)]_2 and 3-6-bis(dimethylamino)acridine. The polymers had inherent viscosities of 1.77 to 2.11 and were soluble in most polar solvents. The glass transition temperatures were in the range of 204 to 298 °C and the 10% weight loss in the range of 506-626 °C, depending upon the structure of the dianhyride monomer. The catalytic activity of the polyimides tested in a hydrosilylation reaction of acetophenone was up to 90%. Leaching of ruthenium into the reaction …

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Structure Of 1-(Thiophen-2-Ylmethyl)-2-(Thiophen-2-Yl)-1h-Benzimidazole, Necmi̇ Dege, Memet Şekerci̇, Süleyman Servi̇, Muharrem Di̇nçer, Ünzi̇le Demi̇rbaş Jan 2006

Structure Of 1-(Thiophen-2-Ylmethyl)-2-(Thiophen-2-Yl)-1h-Benzimidazole, Necmi̇ Dege, Memet Şekerci̇, Süleyman Servi̇, Muharrem Di̇nçer, Ünzi̇le Demi̇rbaş

Turkish Journal of Chemistry

The title compound, C_{16}H_{12}N_2S_2, crystallizes in the monoclinic space group P2_1/n with Z = 4, a = 8.950 (5) Å, b = 9.141 (5) Å, c = 17.429 (5) Å and \beta = 93.638 (5)°. The benzimidazole ring is essentially planar. The crystal structure is stabilized by intermolecular C---H ... N and C---H ... \pi contacts.

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Studies On 2-Ethyl-3-Carbmethoxy-4-Aryl-5-Oxo-1,4,5,6,7,8-Hexahydroquinoline Derivatives And Calcium Modulatory Activities, Ci̇hat Şafak, Elvan Doğan, Kevser Erol Jan 2006

Studies On 2-Ethyl-3-Carbmethoxy-4-Aryl-5-Oxo-1,4,5,6,7,8-Hexahydroquinoline Derivatives And Calcium Modulatory Activities, Ci̇hat Şafak, Elvan Doğan, Kevser Erol

Turkish Journal of Chemistry

Twelve new compounds having a 2-ethyl-3-carbmethoxy-4-aryl-5-oxo-1,4,5,6,7,8-hexahydroquinoline structure were synthesized, characterized and screened for their calcium modulatory activities. The calcium antagonistic activities of the compounds were investigated by tests performed on isolated rat ileum and lamb carotid artery. Compounds 1, 4, 8 and 9 showed considerable activity.

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