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2012

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Articles 10831 - 10860 of 12196

Full-Text Articles in Physical Sciences and Mathematics

Age Composition And Distribution Of Red Drum (Sciaenops Ocellatus) In Offshore Waters Of The North Central Gulf Of Mexico: An Evaluation Of A Stock Under A Federal Harvest Moratorium, Sean P. Powers, Crystal Hightower, J. Marcus Drymon, Matthew W. Johnson Jan 2012

Age Composition And Distribution Of Red Drum (Sciaenops Ocellatus) In Offshore Waters Of The North Central Gulf Of Mexico: An Evaluation Of A Stock Under A Federal Harvest Moratorium, Sean P. Powers, Crystal Hightower, J. Marcus Drymon, Matthew W. Johnson

University Faculty and Staff Publications

Because of a lack of fishery- dependent data, assessment of the recovery of fish stocks that undergo the most aggressive form of management, namely harvest moratoriums, remains a challenge. Large schools of red drum (Sclaenops ocellatus) were common along the northern Gulf of Mexico until the late 1980s when increased fishing effort quickly depleted the stock. After 24 years of harvest moratorium on red drum in federal waters, the stock is in need of reassessment; however, fishery dependent data are not available in federal waters and fishery-independent data are limited. We document the distribution, age composition, growth, and condition of …

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Properties Of Weighted Generalized Beta Distribution Of The Second Kind, Yuan Ye Jan 2012

Properties Of Weighted Generalized Beta Distribution Of The Second Kind, Yuan Ye

Electronic Theses and Dissertations

Author's abstract: In this thesis, a new class of weighted generalized beta distribution of the second kind (WGB2) is presented. The construction makes use of the conservability approach' which includes the size or length-biased distribution as a special case. The class of WGB2 is used as descriptive models for the distribution of income. The results that are presented generalize the generalized beta distribution of second kind (GB2). The properties of these distributions including behavior of pdf, cdf, hazard functions, moments, mean, variance, coefficient of variation (CV), coefficient of skewness (CS), coefficient of kurtosis (CK) are obtained. The moments of other …

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Nonlinear Dynamics And Stochasticity Of Core Genetic Regulation, Hongguang Xi Jan 2012

Nonlinear Dynamics And Stochasticity Of Core Genetic Regulation, Hongguang Xi

Mathematics Theses

Bacillus subtilis is one of the very well-studied organisms in biology. Recent results show that an alternative competence regulation circuit for this bacterium, differing only in the order of the composite negative feedback loop onto the master competence regulator gene comK, despite presenting equivalent functionality, exhibits physiologically important differences.It is not clear why Nature only selects a specific gene regulation circuit other than a plethora of equivalent others. Here, we hope, from the point of view of reverse engineering, to discover the fundamental reasons for natural selection of a particular circuit structure over another. Based on the wild-type Bacillus subtilis …

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Optomechanics Of Cavity Driven Nanoparticles, Joel T. Rubin Jan 2012

Optomechanics Of Cavity Driven Nanoparticles, Joel T. Rubin

Dissertations, Theses, and Capstone Projects

The subject of this thesis is the opto-mechanical interaction of a spherical high-Q microresonator and a subwavelength particle, which, at optical wavelengths, corresponds to a size on the order of nanometers. After a review of the basic theory of spherical resonators and multi-sphere scattering, the full self-consistent electromagnetic field of the coupled resonator-particle system is derived. The particle-induced frequency shift and broadening is calculated by examining the poles of the scattering coefficients of the resonator. The force exerted on the particle by the field is determined via the Maxwell stress tensor, and is found to be in general non-conservative. From …

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Ruthenium(Ii) Polypyridyl Complexes As Potential Anticancer Drugs: Synthesis, Characterization, Cell Permeability And Investigation Of Their Hypoxia-Selectivity, Yanling Chen Jan 2012

Ruthenium(Ii) Polypyridyl Complexes As Potential Anticancer Drugs: Synthesis, Characterization, Cell Permeability And Investigation Of Their Hypoxia-Selectivity, Yanling Chen

Chemistry & Biochemistry Theses

Research on biological activity of ruthenium polypyridyl complexes (RPCs) continues to attract interest as these complexes have shown promising anti-cancer activity both in vitro and in vivo. The mononuclear RPC, [(phen)₂Ru(tatpp)]²⁺ (MP) and the related dinuclear complex [(phen)₂Ru(tatpp)Ru(phen)₂]⁴⁺ (P) have been shown to both intercalate with DNA and show potentiated DNA cleavage under anaerobic and reducing conditions¹ ² as well as show good selectivity and cytotoxicity towards malignant cell lines in vitro and tumors in vivo. Both complexes contain the redox-active tatpp ligand which is thought to be the essential component for the observed biological activity. This thesis is focused …

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Applications Of Circular Dichroism (Cd) Spectroscopy As An Educational Tool For Undergraduate Students And Monitoring Protein Conformational Changes Induced By Ligand Binding, Catherine Ann Van Der Kar Jan 2012

Applications Of Circular Dichroism (Cd) Spectroscopy As An Educational Tool For Undergraduate Students And Monitoring Protein Conformational Changes Induced By Ligand Binding, Catherine Ann Van Der Kar

Chemistry & Biochemistry Theses

The work reported here provides an overview on the applications of circular dichroism (CD) spectroscopy for the study of protein secondary structure. This project has two specific goals. First, to develop and validate an undergraduate experiment for CHEM 3175 (biophysical chemistry laboratory) to demonstrate the use of CD spectroscopy for the determination of protein secondary structure. In an extension of this work, the same principles of analysis were applied to the study and characterization of the protein-ligand interaction of MiaE (a non-heme iron hydroxylase) and its substrate, tRNA.

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Photo-Driven One And Two-Electron Processes Of Tetraazatetrapyridopentacene And Substituted Dipyridophenazine Ligands In The Presence Or Absence Of Zinc And Ruthenium Complexation, Joseph M. Aslan Jan 2012

Photo-Driven One And Two-Electron Processes Of Tetraazatetrapyridopentacene And Substituted Dipyridophenazine Ligands In The Presence Or Absence Of Zinc And Ruthenium Complexation, Joseph M. Aslan

Chemistry & Biochemistry Dissertations

Herein, we report the interaction of light with Zn(II) and Ru(II) adducts of the polypyridal ligands tetraazatetrapyridopentacene (tatpp) and dipyridophenazine (dppz). For examples where Zn(II) is coordinated to tatpp and dppz, we have established a kinetic isotope effect for photo-oxidation of alcohols using both metal-free and metal-bound complexes of tatpp and dppz. The data supports H-atom transfer mechanism in the absence of Zn(II), and a formal "hydride" transfer in the presence of Zn(II).We also report herein the synthesis and characterization of various [Ru(phen)2(dppzX2)]2+ complexes using analytical techniques such as NMR, ESI-MS, CHN, and UV/Vis. We have chemically and electrochemically generated …

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Integrated Chemostratigraphy And Paleoceanography Of The Mississippian Barnett Formation, Krystin Chantel Robinson Jan 2012

Integrated Chemostratigraphy And Paleoceanography Of The Mississippian Barnett Formation, Krystin Chantel Robinson

Earth & Environmental Sciences Theses

The Barnett Formation was deposited on a gently sloping marine margin that ultimately became the Fort Worth Basin (FWB), a foreland basin that evolved during the late Paleozoic Era. The FWB formed as a result of the early Ouachita Orogeny, due to the collision of Laurasia and Gondwana. The Mississippian Barnett Formation is an organic-rich lithologic unit composed primarily of laminated siliceous mudrock with some calcareous mudrock intervals. The objective of the project is to develop and interpret stratigraphic changes in the geochemistry of the Barnett Formation for the purposes of understanding the paleoceanography of the northernmost Fort Worth Basin, …

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Heavy Metal Contamination Of Road Dust In Lanzhou, China, Michael Hiett Jan 2012

Heavy Metal Contamination Of Road Dust In Lanzhou, China, Michael Hiett

Earth & Environmental Sciences Theses

Road dusts were collected from the streets of the city of Lanzhou, the capital and largest city of Gansu Province in Northwest China. The potential health hazard posed by contaminated road dusts may be considerable for certain sensitive populations. Specifically young children who, while exploring their environment by mouthing and touching, may inadvertently ingest polluted soils and dusts through hand-to-mouth-activity, and through mouthing contaminated objects. Lanzhou, once ranked as one of the 10 most polluted cities in the world, clearly has, in all likelihood many locales with elevated levels of pollutants in various environmental media (e.g., air, water, soil and …

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Bad Boundary Behavior In Star Invariant Subspaces Ii, William T. Ross, Andreas Hartmann Jan 2012

Bad Boundary Behavior In Star Invariant Subspaces Ii, William T. Ross, Andreas Hartmann

Department of Math & Statistics Faculty Publications

We continue our study begun in [HR11] concerning the radial growth of functions in the model spaces (IH2)⊥.

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Unitary Equivalence To A Truncated Toeplitz Operator: Analytic Symbols, William T. Ross, Stephan Ramon Garcia, Daniel E. Poore Jan 2012

Unitary Equivalence To A Truncated Toeplitz Operator: Analytic Symbols, William T. Ross, Stephan Ramon Garcia, Daniel E. Poore

Department of Math & Statistics Faculty Publications

Unlike Toeplitz operators on H2, truncated Toeplitz operators do not have a natural matricial characterization. Consequently, these operators are difficult to study numerically. In this note we provide criteria for a matrix with distinct eigenvalues to be unitarily equivalent to a truncated Toeplitz operator having an analytic symbol. This test is constructive and we illustrate it with several examples. As a byproduct, we also prove that every complex symmetric operator on a Hilbert space of dimension < 3 is unitarily equivalent to a direct sum of truncated Toeplitz operators.

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Proximity Of Cancer Cases To Airports Within The State Of Texas, Sala Nanyanzi Senkayi Jan 2012

Proximity Of Cancer Cases To Airports Within The State Of Texas, Sala Nanyanzi Senkayi

Earth & Environmental Sciences Dissertations

Determining whether the incidence of cancer may be associated with pollutants emitted from airports is important in order to better plan cities to reduce such incidences. This research aims to answer the following questions: 1) Is there a trend between the incidence of various kinds of cancer and proximity to air emission sources, including airports, in Texas? and 2) Specifically, is there a relationship between childhood leukemia and airport benzene emissions? Texas has two airports ranked among the top 10 U.S. airports in terms of enplanements for Jan.-March 2010: Houston ranked 7th, while Dallas was 3rd . State-wide cancer incidence …

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Spin Coupling By Conduction Electrons Explored By Double Time Green's Functions, William Robert Decker Jan 2012

Spin Coupling By Conduction Electrons Explored By Double Time Green's Functions, William Robert Decker

Physics Theses

The impurities containing unfilled d or f shells may have localized magnetic moments in nonmagnetic metals, semiconductors, and superconductors under certain conditions. These localized moments interact with each other through the spin polarization field of conduction electrons. The indirect coupling between magnetic impurities is referred to as the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction which is important in describing the magnetic and thermodynamic properties of magnetic nanostructures. The interaction may be expressed as a long range oscillatory function. I explored the properties of the indirect exchange interaction between localized moments in different dimensions using the s-d model and the Green's functions method. An …

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Applications Of A Laser Microbeam In The Study Of Degeneration, Regeneration, And Guidance Of Primary Cns Axons, Bryan James Black Jan 2012

Applications Of A Laser Microbeam In The Study Of Degeneration, Regeneration, And Guidance Of Primary Cns Axons, Bryan James Black

Physics Theses

This thesis explores the applications of a near infrared (NIR) laser microbeam as a tool for manipulating primary axons by initiating femtosecond pulsed-laser plasma-mediated ablation (laser axotomy) and optical guidance. Chapter 1 briefly introduces axon morphology, growth, and the principles of axon guidance, as well as an introduction to the unique capabilities/potential provided by laser microbeams in biological research (laser-tissue interactions). Non-linear, multiphoton absorption processes are discussed in context of biological tissue ablation. In addition, we discuss specific challenges facing mammalian central nervous system (CNS) axons subsequent to injury, and comment on strategies which can be employed to mitigate, remove, …

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Two-Photon Optogenetic Stimulation Of Cells, Kamal Raj Dhakal Jan 2012

Two-Photon Optogenetic Stimulation Of Cells, Kamal Raj Dhakal

Physics Theses

The controlled stimulation of cells, especially neurons, is of significant interest both for basic understanding of neuronal circuitry as well as clinical interventions. Existing electrode-based methods of stimulation are invasive and non-specific to highly localized regions or specific cell types. Recently, optical stimulation of targeted neurons expressing light-sensitive proteins (opsins) using visible light has emerged as a powerful technique in neuroscience. However, the use of these optogenetic tools as a minimally invasive technique for in-vivo applications is limited to the study/intervention of superficial regions of the brain since, due to absorption and scattering, a significant amount of the visible light …

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Student Enrolment In Classes With Frequent Mathematical Discussion And Its Longitudinal Effect On Mathematics Achievement, Karl W. Kosko Jan 2012

Student Enrolment In Classes With Frequent Mathematical Discussion And Its Longitudinal Effect On Mathematics Achievement, Karl W. Kosko

The Mathematics Enthusiast

Mathematical discussion has been identified as being beneficial to students’ understandings of mathematics (Goos, 1995; Lee, 2006). Students in classrooms with more effective math discussion have been observed to engage more frequently in discussion (e.g. Hiebert & Wearne, 1993), but the converse is not necessarily true (e.g. Manouchehri & St. John, 2006). Utilizing hierarchical linear modeling, the present study examined student enrollment in classes with more and less frequent discussion and such enrollment’s effect on mathematics achievement over time. Results indicated that students enrolled in classes that discuss math “almost every day” consistently have higher math achievement than students enrolled …

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Reflections On Teaching With A Standards-Based Curriculum: A Conversation Among Mathematics Educators, Jill Newton, Ricki Geller, Lindsay Umbeck, Lisa Kasmer Jan 2012

Reflections On Teaching With A Standards-Based Curriculum: A Conversation Among Mathematics Educators, Jill Newton, Ricki Geller, Lindsay Umbeck, Lisa Kasmer

The Mathematics Enthusiast

Many teachers and researchers have written about the challenges inherent in adopting new teaching practices in mathematics classrooms (e.g., Chazan, 2000; Clarke, 1997; Heaton, 2000). The authors of this article, all with secondary mathematics teaching experience, are convinced by research suggesting that Standards-based mathematics curricula are beneficial for student learning.1 However, the first three authors had not used such curriculum materials in their own classrooms, and we desired experience using a Standards-based mathematics curriculum with secondary students. To this end, we taught a week-long summer course with a focus on linear functions to high school students who had previously struggled …

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Histological Evaluation Of The Biocompatibility Of Polyurea Crosslinked Silica Aerogel Implants In A Rat Model: A Pilot Study, Firouzeh Sabri, J. D. Boughter Jr., D. Gerth, O. Skalli, T. C. N. Phung, G. R. M. Tamula, Nicholas Leventis Jan 2012

Histological Evaluation Of The Biocompatibility Of Polyurea Crosslinked Silica Aerogel Implants In A Rat Model: A Pilot Study, Firouzeh Sabri, J. D. Boughter Jr., D. Gerth, O. Skalli, T. C. N. Phung, G. R. M. Tamula, Nicholas Leventis

Chemistry Faculty Research & Creative Works

Background: Aerogels are a versatile group of nanostructured/nanoporous materials with physical and chemical properties that can be adjusted to suit the application of interest. In terms of biomedical applications, aerogels are particularly suitable for implants such as membranes, tissue growth scaffolds, and nerve regeneration and guidance inserts. The mesoporous nature of aerogels can also be used for diffusion based release of drugs that are loaded during the drying stage of the material. From the variety of aerogels polyurea crosslinked silica aerogels have the most potential for future biomedical applications and are explored here. Methodology: This study assessed the short and …

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Use Of Georphysics To Map Subsurface Features At Levee Seepage Locaitons, Thomas Chapman Brackett Jan 2012

Use Of Georphysics To Map Subsurface Features At Levee Seepage Locaitons, Thomas Chapman Brackett

Electronic Theses and Dissertations

The Great Flood of 2011 caused moderate to severe seepage and piping along the Mississippi River levees in Northwest Mississippi. The aim of this thesis was to implement geophysical techniques at two seepage locations in order to give a better understanding of the causes of underseepage and information on how to mitigate the problem. Sites near Rena Lara in Coahoma County and near Francis in Bolivar County were chosen to conduct this survey. Electrical Resistivity Tomography (ERT) and Electromagnetic Induction (EM) surveys were conducted on and adjacent to levees to identify seepage pathways and any dominant geological features at the …

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Description Of Coherent Structures In The Atmospheric Boundary Layer By Model Reduction Of The Surface Pressure, Gregory William Lyons Jan 2012

Description Of Coherent Structures In The Atmospheric Boundary Layer By Model Reduction Of The Surface Pressure, Gregory William Lyons

Electronic Theses and Dissertations

The flow of coherent turbulent structures into a wind turbine is associated with vibrational blade excitation. Successful forecasting of such turbulent events for control system input would increase the lifetime of turbine components. The coherence of these features suggests description by model reduction. To this end, an array of pressure transducers was deployed on the ground at Reese Technology Center in Lubbock, Texas, and the pressure fluctuations were recorded over nearly two diurnal cycles. A program for computation of the dynamic mode decomposition was developed with special consideration for the case of a non-stationary, nonlinear system. A simulated surface-pressure perturbation …

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Synthesis And Characterization Of Nickel Complexes With Relevance To Nickel Acireductone Dioxygenase And Nickel Superoxide Dismutase, Margo Nicole Montgomery Jan 2012

Synthesis And Characterization Of Nickel Complexes With Relevance To Nickel Acireductone Dioxygenase And Nickel Superoxide Dismutase, Margo Nicole Montgomery

Electronic Theses and Dissertations

This research presents an investigation of synthetic model complexes with relevance to the active site of Ni(II) acireductone dioxygenase (Ni-ARD) and Ni(II) superoxide dismutase (Ni-SOD). Acireductone dioxygenases (ARDs) are a unique set of enzymes found in the methionine salvage pathway that catalyze the oxidation reaction of acireductone (1, 2-dihydroxy-3-oxo-5-(methylthio)pent-1-ene). These enzymes share a compolypeptide sequence but bind different metal ions, Ni2+ or Fe2+, at the active site. The Ni-ARD enzyme is responsible for the off pathway shunt in the pathway. Using the tridentate nitrogen donor ligands hydrotris(3,5-dimethyl-1-pyrazolyl)borate (Tp*) and the newly developed tris(1, 2-dimethyl-4-imadozyl)carbinol, (4-TICMe, Me) several reactions involving the …

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Comparison Of Apple's Ios 5 And Android For Mobile Applications Development: A Developer's Perspective, Estela Pochintesta Jan 2012

Comparison Of Apple's Ios 5 And Android For Mobile Applications Development: A Developer's Perspective, Estela Pochintesta

Electronic Theses and Dissertations

Body composition, or the proportion of fat, muscle, and bone of an individual's body, is an important indication of health status. Numerous techniques can be used to assess body composition, producing varied results and measurements. For individuals with insufficient or excessive amounts of body fat, accurate assessment of body composition is crucial. Two commonly used techniques for measuring body composition are air displacement plethysmography (adp) and dual-energy x-ray absorptiometry (dxa). Past research has been conducted, comparing adp and dxa, but the results are inconsistent. The majority of past studies found that, when compared to dxa, adp underestimated body fat percentage, …

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Four-Component Synthesis Of 1,3,4-Oxadiazole Derivatives From N-Isocyaniminotriphenylphosphorane, Aromatic Carboxylic Acids, Aromatic Bis-Aldehydes, And Secondary Amines, Ali Ramazani, Zahra Karimi, Ali Souldozi, Yavar Ahmadi Jan 2012

Four-Component Synthesis Of 1,3,4-Oxadiazole Derivatives From N-Isocyaniminotriphenylphosphorane, Aromatic Carboxylic Acids, Aromatic Bis-Aldehydes, And Secondary Amines, Ali Ramazani, Zahra Karimi, Ali Souldozi, Yavar Ahmadi

Turkish Journal of Chemistry

The 1:1 iminium intermediate generated by the addition of a secondary amine to aromatic bis-aldehydes (isophthalaldehyde and terphthalaldehyde) is trapped by the N-isocyaniminotriphenylphosphorane in the presence of a aromatic carboxylic acid derivative, which leads to the formation of corresponding iminophosphorane intermediate. Then disubstituted 1,3,4-oxadiazole derivatives are formed via intramolecular aza-Wittig reaction of the iminophosphorane intermediates. The reactions were completed in neutral conditions at room temperature and the corresponding disubstituted 1,3,4-oxadiazole derivatives were produced in excellent yields.

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Synthesis Of \Alpha-Aminonitriles Catalyzed By Montmorillonite K10 In The Presence Of Dicationic Phosphonium Salt In Water Under Ultrasonic Effect, Çi̇ğdem Yildirim, Çi̇ğdem Yolaçan, Feray Aydoğan Jan 2012

Synthesis Of \Alpha-Aminonitriles Catalyzed By Montmorillonite K10 In The Presence Of Dicationic Phosphonium Salt In Water Under Ultrasonic Effect, Çi̇ğdem Yildirim, Çi̇ğdem Yolaçan, Feray Aydoğan

Turkish Journal of Chemistry

The synthesis of \alpha-aminonitriles was successfully accomplished by the 1-pot 3-component reaction of several aldehydes with (S)-\alpha-phenylethylamine and sodium cyanide in water in the presence of montmorillonite K10 and dicationic phosphonium salt under ultrasonic effect with good yields and moderate diastereoselectivities.

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Comparative Photodecolorization Of Red Dye By Anatase, Rutile (Tio_2), And Wurtzite (Zno) Using Response Surface Methodology, Shahab Khameneh Asl, Sayad Khatib Sadrnezaad, Mansour Keyanpour-Rad, Deni̇z Üner Jan 2012

Comparative Photodecolorization Of Red Dye By Anatase, Rutile (Tio_2), And Wurtzite (Zno) Using Response Surface Methodology, Shahab Khameneh Asl, Sayad Khatib Sadrnezaad, Mansour Keyanpour-Rad, Deni̇z Üner

Turkish Journal of Chemistry

Treatment of dye pollution containing C.I. Acid Red 14 (AR14) by a coupled photocatalytic process was studied. Titanium dioxide, in the form of anatase and rutile, and zinc oxide, were used as photocatalysts. The investigated photocatalysts were Aldrich-produced nanopowders with crystallites of a mean size of 20-30 nm and a specific surface area of about 50 m^2/g. A comparison of TiO_{2(anatase)}, TiO_{2(rutile)}, TiO_{2(a,r)}, and ZnO for the decolorization of the AR14 solution was performed. Results showed that color removal followed the decreasing order of TiO_{2(a,r)}, ZnO > TiO_{2(a,r)} > TiO_{2(a)}, ZnO > TiO_{2(r)}, ZnO >TiO_{2(a,r)} > TiO_{2(a)} > ZnO > TiO_{2(r)}. Response surface methodology (RSM) was …

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A Dft Study On The Structural And Optical Properties And Cation Selectivities Of Some Metal-Coumarin-Crown Ether Complexes, Emi̇ne Esra Kasapbaşi, Mi̇ne Yurtsever Jan 2012

A Dft Study On The Structural And Optical Properties And Cation Selectivities Of Some Metal-Coumarin-Crown Ether Complexes, Emi̇ne Esra Kasapbaşi, Mi̇ne Yurtsever

Turkish Journal of Chemistry

Macrocyclic ethers are well-known molecules because of their high cation-binding capacities. They form stable complexes with alkaline and soil alkaline metals through strong oxygen bridges in solution. For enhanced optical properties, a new series of crown ethers was synthesized with a coumarin ring fused to it. The effects of the position of the coumarin ring, the type of the substituent on the coumarin ring, and the size of the crown on the optical properties of the material were studied according to the density functional theory (DFT) method at the B3LYP/6-31g(d) level of theory in the gas phase as well as …

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Surfactant-Sensitized Spectrophotometric Determination Of Hg(Ii) In Water Samples Using 2-(2-Thiazolylazo)- P-Cresol As Ligand And Cetylpyridinium Chloride As Cationic Surfactant, Ramazan Gürkan, Tuğba Çepken, Hali̇l İbrahi̇m Ulusoy Jan 2012

Surfactant-Sensitized Spectrophotometric Determination Of Hg(Ii) In Water Samples Using 2-(2-Thiazolylazo)- P-Cresol As Ligand And Cetylpyridinium Chloride As Cationic Surfactant, Ramazan Gürkan, Tuğba Çepken, Hali̇l İbrahi̇m Ulusoy

Turkish Journal of Chemistry

A new, reliable, surfactant-sensitized method is described for the spectrophotometric determination of total and dissolved inorganic mercury at trace levels. The method is based on the ternary complex formation of Hg(II) with 2-(2-thiazolylazo)-p-cresol and a cationic surfactant, cetylpyridinium chloride, at pH 9.5. The detection and quantification limits of the method with surfactant were 6 and 19 \mu g L^{-1}, while those of the method without surfactant were 22 and 67 \mu g L^{-1}, respectively. The method obeys Beer's law at up to approximately 10 mg L^{-1} Hg(II) in an aqueous surfactant medium. The relative errors and relative standard deviations of …

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Synthesis, Characterization, And Microwave-Promoted Catalytic Activity Of Novel Benzimidazole Salts Bearing Silicon-Containing Substituents In Heck-Mizoroki And Suzuki-Miyaura Cross-Coupling Reactions Under Aerobic Conditions, Hasan Küçükbay, Ni̇hat Şi̇reci̇, Ülkü Yilmaz, Selma Deni̇z, Mehmet Akkurt, Zeli̇ha Baktir, Orhan Büyükgüngör Jan 2012

Synthesis, Characterization, And Microwave-Promoted Catalytic Activity Of Novel Benzimidazole Salts Bearing Silicon-Containing Substituents In Heck-Mizoroki And Suzuki-Miyaura Cross-Coupling Reactions Under Aerobic Conditions, Hasan Küçükbay, Ni̇hat Şi̇reci̇, Ülkü Yilmaz, Selma Deni̇z, Mehmet Akkurt, Zeli̇ha Baktir, Orhan Büyükgüngör

Turkish Journal of Chemistry

A number of benzimidazole derivatives (1-8) were synthesized and the catalytic activity of these compounds in a catalytic system including Pd(OAc)_2 and K_2CO_3 in DMF-H_2O was evaluated in Heck-Mizoroki and Suzuki-Miyaura cross-coupling reactions of aryl iodides, bromides, and chlorides with styrene and arylboronic acids under microwave irradiation and aerobic conditions. The yields of both the Heck-Mizoroki and the Suzuki-Miyaura cross coupling reactions with aryl iodides and aryl bromides were nearly quantitative. The synthesized 1-substituted benzimidazole (1) and benzimidazole salts (2-8) were identified by ^1H- and ^{13}C-NMR and IR spectroscopic methods, and micro analysis. The molecular structure of 7 was also …

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Preparation And Antimicrobial Activity Evaluation Of Some Quinoline Derivatives Containing An Azole Nucleus, Muhammet Özyanik, Serpi̇l Demi̇rci̇, Hakan Bektaş, Nesli̇han Demi̇rbaş, Ahmet Demi̇rbaş, Şengül Alpay Karaoğlu Jan 2012

Preparation And Antimicrobial Activity Evaluation Of Some Quinoline Derivatives Containing An Azole Nucleus, Muhammet Özyanik, Serpi̇l Demi̇rci̇, Hakan Bektaş, Nesli̇han Demi̇rbaş, Ahmet Demi̇rbaş, Şengül Alpay Karaoğlu

Turkish Journal of Chemistry

Quinoline-2-carbohydrazide (2) obtained from quinaldic acid (1) was converted to the corresponding carbothioamide 3 and carboxamide 6 by treatment with benzyliso(thio)cyanate. The basic treatment of 3 and 6 yielded the corresponding 1,2,4-triazole derivatives 4 and 7. The synthesis of 5-(quinolin-2-yl)-1,3,4- oxadiazol-2-thiol (9) was performed from the reaction of 1 with CS_2 in basic media. The Mannich reaction of compounds 4, 7, and 9 resulted in the formation of aminoalkylated derivatives 5a-c, 8, and 10a,b. The condensation of 1 with thiosemicarbazide, carbohydrazide, or thiocarbohydrazide gave the corresponding 1,2,4-triazole derivatives (11-13). The treatment of 4-amino-5-(quinolin-2-yl)- 4H-1,2,4-triazole-3-thiol (13) with 4-chlorophenacyl bromide caused the …

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Synthesis And Evaluation Of Enzyme Inhibitory Potential Of Some Derivatives Of Scopolamine, Durre Shahwar, Muhammad Asam Raza, Tania Khan Jan 2012

Synthesis And Evaluation Of Enzyme Inhibitory Potential Of Some Derivatives Of Scopolamine, Durre Shahwar, Muhammad Asam Raza, Tania Khan

Turkish Journal of Chemistry

This study was designed to synthesize and evaluate derivatives of scopolamine (1) as acetylcholine esterase and protease inhibitors. Scopolamine (1) was extracted from the aerial parts of Datura innoxia through bioassay guided fractionation. Five different derivatives of scopolamine (1) were synthesized, and identified through spectroscopic studies. Their acetylcholine esterase (AChE) and trypsin inhibitory potentials were determined through standard protocols and evaluated from the perspective of structure-activity relationship. The synthesized scopolamine derivatives (2-6) showed remarkable AChE inhibitory activity, except for scopoline (6). The results showed higher enzyme inhibition potential of the synthesized compounds (2-5) as compared to scopolamine (1). Maximum inhibition …

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