Physical Sciences and Mathematics Commons^™

Carbonic Anhydrase From Nicotiana Tabacum Leaves, Nazan Demi̇r, Yaşar Demi̇r

Turkish Journal of Chemistry

In this study, carbonic anhydrase (CA: carbonate hydrolyase; E.C.4.2.1.1) was purified from adult {\it Nicotiana tabacum} leaves and studied biochemically. The enzyme was purified twice times by using (NH$_4)_2SO_4 precipation and DEAE-cellulose column chromatography, and its activity was determined for two different substrates (CO_2 and p-nitrophenyl acetate). The enzyme obtained from the ion exchange column was purified 40.7 fold and the purity was controlled by 3\%-10\% discontinuous SDS-PAGE. The pH of the purified enzyme varied between 6.0 and 7.2, the optimum being 6.9. V_{max} and K_m values were calculated with p-nitrophenyl acetate (0.1524 mM, 0.5446 mM, respectively) as substrate. The …

Determination Of Ponceau 4r And Tartrazine In Various Food Samples By Derivative Spectrophotometric Methods, Sedat Sayar, Yüksel Özdemi̇r

Turkish Journal of Chemistry

Derivative spectrophotometric methods were originally developed for determining Ponceau 4R and Tartrazine in order to resolve their binary mixtures. The method permits the simultaneous determinations of these food colorants in various food samples. Recovery by derivative methods was nearly 100 \%.

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.

^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.

Some Remarks On Solid State Polymerization, George Adler

Turkish Journal of Chemistry

No abstract provided.

Calculation Of Spreading Pressure Of Water On Cellulosic Films From Contact Angle Data, H. Yıldırım Erbi̇l

Turkish Journal of Chemistry

The correlations between the surface properties of the modified cellulose papers with their toner compatibility were investigated. The surface tension components of the cellulosic films, their interfacial tension with the liquid drops and the work of adhesion components were calculated using van Oss-Good's One-Liquid contact angle approach. The electron donor (or Lewis base) \gamma^- components of the cellulosic films were found to represent the main interactions with the the electron acceptor (acidic) \gamma^+ components of the contacting liquids. Allyl ketene dimer (AKD) grafting of the cellulose affected the surface properties; the higher the substitution of the hydroxyl group, the smaller …

A Quantum-Chemical Investigation On 5,5'-Bi(1h-1.2,4-Triazole)), A. A. İki̇zler, R. Abbasoğlu, N. Saltek, M. Şeri̇fova

Turkish Journal of Chemistry

The conformational analysis of flexible 5,5'-bi(1H-1,2,4-triazole) molecule containing various reaction centers has been performed by the semiempirical methods MNDO,AM1 and PM3, and the internal rotation barrier calculated. The most stable conformation of the molecule has been determined to be the planar trans conformation. According to the three methods, 5,5'-bi(1H-1,2,4-triazole) molecule (C) has been found to be relatively more stable than its tautomer 3,3'-bi(1H-1,2,4-triazole)(B) and to be less stable than its other tautomer 3,3'-bi(4H-1,2,4-triazole)(A). Moreover, the electronic properties of 5,5'-bi(1H-1,2,4-triazole) molecule and the effect of conformational changing on electronic and geometric properties have also been investigated. To determine the protonation sites …

The Reliability Of Jung-Biggs-Moorhead Method For Cholesterol Determination In The Presence Of Ergosterol, Lemi Türker, Şahinde Demi̇rci̇, Marjan Akdağ

Turkish Journal of Chemistry

In the present study, the reliability of Jung-Biggs-Moorhead method for cholesterol determination has been tested in the presence of another steroid, ergosterol. It was observed that presence of ergosterol interferes with the absorbance measurement of cholesterol. When both steroids are present in the sample maximum absorption wavelength are not shifted by the mutual interaction but absorbance values are changed considerably. Therefore this method may be used only for qualitative bu not quantitative analysis for cholesterol in the presence of ergosterol.

Synthesis And Characterisation Of Anhydrous Magnesium Phosphate Mg$_3$(Po$_4$)$_2$, A. Baykal, M. Kizilyalli, R. Kniep

Turkish Journal of Chemistry

The synthesis and characterization of anhydorus Mg_3(PO$_4)_2 was investigated. Mg_3(PO$_4)_2 is reported to have similar structural arrangements with Co_3(PO_4)_2 and \gamma-Zn_3(PO_4)_2 compounds. The sample was prepared by a new technique which is the reaction of MgCl_2.6H_2O and Na_3PO_4.12H_2O solutions at pH=5.1, which was adjusted by adding concentrated H_3PO_4 to the reaction mixture and heating the precipitated product at 600^{\circ}C untill constant weight. The purity of the product was checked by X-ray powder diffraction, IR, density measurement, SEM and DTA analysis. The monoclinic unit cell dimensions of product are a=7.605 (2), b=8.233 (3), c=5.080 (1)A^{\circ} and \beta= 94.19^{\circ} (3), which was …

Hydrolysis And Condensation Reactions Of Methacrylate-Modified Aluminum Alkoxides, Ertuğrul Arpaç, Efraim Avşar

Turkish Journal of Chemistry

The hydrolysis of aluminum tri-sec-butoxide and compounds obtained by substituting the larger functional groups for the present alkly groups in Al(O-sec-Bu)_3, and the reaction of these products with a polymerizable organic ligand, i.e. methacrylic acid, were studied together with the hydrolysis reactions of the final products. A good method of preparing high-tech materials and new composites uses organo-substituted silicon esters and/or alkoxides of various elements in a polycondensation process. Introducing a suitable organic network into the inorganic backbone gives desirable properties in new coating materials. The preparation of such materials is possible via the hydrolysis of metal alkoxides. Usually, different …

Development Of A High-Speed Ultraviolet Spectrometer, Capable Of Real-Time No And Aromatic Hydrocarbon Detection In Vehicle Exhaust (Presentation), Peter J. Popp, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.

The Influence Of Microstructure On The Thermal Degradation Behavior Of Poly(Vinyl Chloride), Hoang Vi Tran

Dissertations, Theses, and Masters Projects

No abstract provided.

N-Methylbenzothiazole-2(3H)-Selone, C8H7Nsse, Steinar Husebye, Sergey V. Lindeman, Martin D. Rudd

Chemistry Faculty Research and Publications

The crystal structure of N-methyl1,3-benzothiazole-2(3H)-selone, (mbts) has been studied to estimate the changes in the molecular geometry of the mbts ligand upon coordination. Hypervalent complexes of mbts with Te^II and I^I have been studied by us previously. A significant elongation of the Se=C bond [from 1.817 (7) in mbts to 1.85-1.88 Å in the complexes] was found, but there were no significant changes in the other geometric parameters of the ligand. The only other bond-length decrease of note was for SeC-NMe [from 1.35 (1) in mbts to 1.32-1.34 Å in the complexes]. Thus, only the …

Glycals : An Extended Study Of The Ferrier-Dimerization, Andreas H. Franz

University of the Pacific Theses and Dissertations

C-linked disaccharides were synthesized from 3,4,6-tri-O-acetyl-D-glucal 1 (1,5- anhydro-3,4,6-tri-O-acetyl-1,2-dideoxy-D-arabino-hex-I-enopyranose), 3,4,6-tri-O- acetyl-D-galactal 2 (1,5-anhydro-3,4,6-tri-O-acetyl-1,2-dideoxy-D-lyxo-hex-1- enopyranose) and 3,4-di-O-acetyl-L-fucal 3 (1,5-anhydro-3,4-di-O-acetyl-1,2,6-tri-deoxy- L-lyxo-hex-1-enopyranose) under Lewis acid catalysis (Scheme 1) and compound 4 was further derivatized at the double bond. Dihydroxylation of the glucose dimer 4 gave high allo-diastereoselectivity. The reactions used in the derivatization of 1 were subsequently applied to 2 and 3. The overall yield of 3 was improved to 70 %. All three glycals (10% solution in toluene) reacted quickly with boron trifluoride to give dimerization products in 40-60% yield. Futile attempts at de-O-acetylation of the 2',3'-unsaturated dimer revealed the necessity of …

Microwave Plasma Chemical Vapor Deposited Diamond Tips For Scanning Tunneling Microscopy, Sacharia Albin, Jianli Zheng, John B. Cooper, Weihai Fu, Arnel C. Lavarias

Electrical & Computer Engineering Faculty Publications

Diamond microparticles were grown on etched tungsten wires using a microwave plasma-assisted chemical vapor deposition process. The apexes on cubo-octahedral particles bound by {100} and {111} facets were effectively used as tunneling tips for scanning tunneling microscopy. The atomically resolved surface image of highly oriented pyrolytic graphite was acquired. Tunneling characteristics revealed a higher electron emission from the diamond tips than that from the platinum–iridium tips. The same diamond tips were used to produce surface indentation and its image. © 1997 American Institute of Physics.

The Thermal Cure Of Phenylethynyl-Terminated Polyimides And Selected Model Compounds, Karen H. Wood

Dissertations, Theses, and Masters Projects

The ability to process high performance polymers into useful adhesives and high quality composites has been significantly advanced by synthetic techniques in which oligomers terminated with reactive groups cure or crosslink at elevated temperature after the article has been fabricated. Several matrix resin systems of considerable interest to the aerospace community utilize phenylethynyl terminated imide (PETI) technology developed at the Langley Research Center to achieve this advantage. This work addresses the cure chemistry of PETI oligomers.;The thermal cure of selected oligomers and model compounds was studied using a variety of analytical techniques including differential scanning calorimetry, high pressure liquid chromatography, …

The Synthesis, Characterization, And Molecular Modeling Of Cyclic Arylene Ether Oligomers, Sheeba Ahmed

Dissertations, Theses, and Masters Projects

Cyclophanes are a family of bridged cyclic aromatic compounds that have found extensive applications in host-guest chemistry, molecular recognition, biomimetics and most recently as precursors in ring-opening polymerizations.;This research presents the synthesis of several novel cyclic arylene ether oligomers, based on 1,3-bis(4-fluorobenzoyl) benzene and 3,3{dollar}\sp\prime{dollar}-methylene diphenol and 3,3{dollar}\sp\prime{dollar}-(ethylene dioxy) diphenol, and their characterization by LC-MS/MS, 1-D {dollar}\sp1{dollar}H-NMR and x-ray crystallography. Electrospray ionization (ES) along with MS/MS was used to characterize cyclic oligomers of molecular weight up to 1600 Da. The thermal properties of these cyclic oligomers were studied by differential scanning calorimetery (DSC) and thermal gravimetric analysis (TGA).;These cyclic oligomers …

The Promotion Of Poly(Methyl Methacrylate) Depolymerization By Metal-Based Initiators, Jason Andrew Macko

Dissertations, Theses, and Masters Projects

No abstract provided.

Asymmetric Synthesis By Palladium (Ii) Catalysis: Chirality Transfer And New A Symmetric Catalytic System, Othman Hamed

Dissertations

No abstract provided.

Surface Morphology Of Gan Films Determined From Quantitative X-Ray Reflectivity, D Lederman, Zhonghai Yu, T H. Myers, Michelle Richards-Babb

Faculty & Staff Scholarship

The surface of two GaN films grown under Ga-rich conditions by molecular beam epitaxywas characterized using x-ray reflectivity, assuming a self-affine/fractal surface morphology. The surface height fluctuations were similar for both samples at the largest lateral length scales at which the fractal description is valid, although this lateral length was significantly greater and the “jaggedness” significantly smaller for the sample grown under higher Ga flux. Previous atomic force microscopy images revealed a higher density of large features on the surface for the sample grown under lower Ga flux. The lateral size of the features are dominated by a convolution of …

The Resolution Of Chiral Dialkylarylsufonium Ions By 1h Nmr Spectroscopy, Johnathan Whetstine

Mahurin Honors College Capstone Experience/Thesis Projects

The goal of this research was to design a rapid Nuclear Magnetic Resonance method to measure enantiomeric excess of chiral sulfonium ions by using chiral lanthanide shift reagents. The sulfonium ions studied were dialkylarylsulfonium ions. The shift reagent that was employed was Europium (III) surrounded by chiral ligands of 3-trifluoroacetyl-d-camphor (tfc), which is derived from (+)-camphor. Ethylmcthylphenylsulfonium ion was synthesized for study as a racemic and enantiomerically enriched mixture. The sulfonium ion was then ion-paired with the shift reagent for resolution of R and S enantiomers. The best resolution was obtained with the Eu(fod)4- shift reagent, with nearly baseline resolution …

Constancy Of Bond Dissociation Energy Ratios For Ab₂/Ab Systems, Danyu Xu

Masters Theses

G2 and G2(MP2) theories have been used to study the bond dissociation energies D⁰_m of a series of AB₂, AB₂⁺, AB₂^-, AB, AB⁺ and AB^- systems. A total of fifty-four molecules and ions have been examined, for which B = O, S or Se and A = C, S, Ge, N⁺, P⁺, As⁺, B^-, Al^- or Ga^-. Each triatomic system has sixteen valence electrons and each diatomic system has ten valence electrons. Both triplet and singlet spin …

Induced Acceleration Of Phosphine Exchange In Metal Carbonyls By Pendant Groups Of Coordinated Polyphosphines, Ping Ye

Masters Theses

The kinetics and thermodynamics of isomerization of (OC)₅CrPPh₂CH₂CH(PPh₂)₂ to its linkage isomer, (OC)₅CrPPh₂CH(PPh₂)CH₂PPh₂, in chloroform-d have been studied with ³¹P{¹H} NMR.

(OC)₅Cr[η¹-PPh₂CH₂CH(PPh₂)₂] ⇄ (OC)5Cr[η¹-PPh₂CH(PPh₂)CH₂PPh₂]

The equilibrium constants for the reaction are 3.60, 2.61, 2.04, and 1.67 at 10 °C, 25 °C, 40 °C, and 53 °C, respectively. The forward reaction becomes more favorable as the temperature …

An Expeditious Synthesis Of Β,Γ-Unsaturated Δ-Lactones: Useful Pharmacological Synthetic Intermediates, Li Xiong

Masters Theses

Two-carbon ring expansions of vinyl β-lactones, were carried out by Lewis acids (BF₃-Et₂O or Et₂AlCl) via an ionization/cation rearrangement. β,γ-unsaturated δ-lactones were produced as efficient protocols for the synthesis of bioactive substances.

Vinyl β-lactones were prepared via ring closure of corresponding unsaturated β-hydroxy acids. Differently structured substrates were examined to study the influence of the substituents on the rearrangement. Other factors, such as temperature, solvent and catalyst were also studied in search of suitable reaction conditions.

This method is moderately successful in providing fused-ring δ-lactones, but higher yields (so far total yield of 24.8%) …

A Chemical Extraction Study Of Lead Contaminated Soil From Granite City, Il, Yan Zhang

Masters Theses

Granite City, IL, surface soil ( 0-10 cm ) contaminated with lead was studied by both single- and a four-step sequential chemical extraction procedures designed to establish the partitioning, mobility and availability of lead in soil. The five fractions corresponding to the selected extractants were exchangeable, carbonates-bound, Fe-Mn oxides bound, organic matter and residual. Lead contamination of the soil was determined as a function of particle size and soil depth.

The contaminated sample had the highest lead content of 573.1 mg/kg at the 4 cm soil depth level, and on average was about 8.8 times that of background soil. Most …

Identification Of Organosulfur Compounds In Illinois Coal, Mandy N. Amin

Masters Theses

The goal of this research was to identify representative organosulfur compounds in Illinois coal which are removed by a mild, chemical desulfurization procedure. Pyridine was used to extract three raw Illinois coals. Coal with a significant amount of elemental sulfur was treated with 1:1 HCl/HF followed by lithium aluminum hydride before pyridine extraction. Pyridine soluble extracts were extracted with tetrahydrofuran. Nickel boride desulfurization was performed on the soluble extracts of the three coals. The before and after desulfurized THF soluble extracts were fractionated and purified by liquid chromatography and the eluents were anlyzed by gas chromatography/mass spectrometry to characterize the …

Azo Dyes Based On 1,10-Phenanthroline, Minchong Mao

Masters Theses

A series of new phenanthroline based azo-dye ligands, produced by diazotizing 5-amino-1,10-phenanthroline (5-NH₂-phen) and then coupling this intermediate to a variety of coupling components, has been synthesized and characterized. The coupling components used were β-naphthol, phenol, and 2,6-dimethylphenol, and the three dye ligands were named phen-azo-β-naphthol, phen-azo-p-phenol, and phen-azo-2,6-dimethylphenol, respectively. ¹H-NMR and IR spectra showed that the dyes exist primarily in the azo form in DMSO solution and as solids. UV-Vis spectra (in MeOH) showed intense (ε ≅ 10⁴ M^-1cm^-1) absorptions ranging from 380 nm to 500 nm for these ligands.

The …

The Synthesis Of 6a,6b-Dideoxy-6 A,6b-(9,10-Dicyanoanthracenyl-2,3-Dimethylene)-Beta-Cyclodextrin, Jonathan D. Tan

Dissertations, Theses, and Masters Projects

No abstract provided.

Semiclassical Approach To The Hydrogen-Exchange Reaction- Reactive And Transition-State Dynamics, Sophya V. Garashchuk, Grossmann Frank, David Tannor

Faculty Publications

Scattering matrix elements and symmetric transition-state resonances for the collinear H ₂ + H → H + H ₂ reaction are obtained using a time-dependent approach. The correlation function between reactant channel wavepackets and product channel wavepackets is used to determine the S-matrix elements. In a similar fashion, autocorrelation functions are used to extract the positions and widths of transition-state resonances. The time propagation of the wavepackets is performed by the improved semiclassical frozen Gaussian method of Herman and Kluk, which is an initial value, uniformly converged method. The agreement between the quantum and semiclassical results is far better …

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.