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2015

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Articles 11401 - 11430 of 12617

Full-Text Articles in Physical Sciences and Mathematics

Relative Drifts And Biases Between Six Ozone Limb Satellite Measurements From The Last Decade, N. Rahpoe, M. Weber, A. V. Rozanov, K. Weigel, H. Bovensmann, J. P. Burrows, A. Laeng, G. Stiller, T. Von Clarmann, E. Kyrölä, V. F. Sofieva, J. Tamminen, K. Walker, D. Degenstein, A. E. Bourassa, R. Hargreaves, P. Bernath, J. Urban, D. P. Murtagh Jan 2015

Relative Drifts And Biases Between Six Ozone Limb Satellite Measurements From The Last Decade, N. Rahpoe, M. Weber, A. V. Rozanov, K. Weigel, H. Bovensmann, J. P. Burrows, A. Laeng, G. Stiller, T. Von Clarmann, E. Kyrölä, V. F. Sofieva, J. Tamminen, K. Walker, D. Degenstein, A. E. Bourassa, R. Hargreaves, P. Bernath, J. Urban, D. P. Murtagh

Chemistry & Biochemistry Faculty Publications

As part of European Space Agency's (ESA) climate change initiative, high vertical resolution ozone profiles from three instruments all aboard ESA's Envisat (GOMOS, MIPAS, SCIAMACHY) and ESA's third party missions (OSIRIS, SMR, ACE-FTS) are to be combined in order to create an essential climate variable data record for the last decade. A prerequisite before combining data is the examination of differences and drifts between the data sets. In this paper, we present a detailed analysis of ozone profile differences based on pairwise collocated measurements, including the evolution of the differences with time. Such a diagnosis is helpful to identify strengths …

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Mass Loss And Chemical Structures Of Wheat And Maize Straws In Response To Ultravoilet-B Radiation And Soil Contact, Guixiang Zhou, Jiabao Zhang, Jingdong Mao, Congzhi Zhang, Lin Chen, Xiuli Xin, Bingzi Zhao Jan 2015

Mass Loss And Chemical Structures Of Wheat And Maize Straws In Response To Ultravoilet-B Radiation And Soil Contact, Guixiang Zhou, Jiabao Zhang, Jingdong Mao, Congzhi Zhang, Lin Chen, Xiuli Xin, Bingzi Zhao

Chemistry & Biochemistry Faculty Publications

The role of photodegradation, an abiotic process, has been largely overlooked during straw decomposition in mesic ecosystems. We investigated the mass loss and chemical structures of straw decomposition in response to elevated UV-B radiation with or without soil contact over a 12-month litterbag experiment. Wheat and maize straw samples with and without soil contact were exposed to three radiation levels: a no-sunlight control, ambient solar UV-B, and artificially elevated UV-B radiation. A block control with soil contact was not included. Compared with the no-sunlight control, UV-B radiation increased the mass loss by 14-19% and the ambient radiation by 9-16% for …

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Molecular Level Characterization Of Diatom-Associated Biopolymers That Bind 234th, ²³³Pa, ²¹°Pb, And 7be In Seawater: A Case Study With Phaeodactylum Tricornutum, Chia-Ying Chuang, Peter H. Santschi, Chen Xu, Yuelu Jiang, Yi-Fang Ho, Patrick G. Hatcher Jan 2015

Molecular Level Characterization Of Diatom-Associated Biopolymers That Bind 234th, ²³³Pa, ²¹°Pb, And 7be In Seawater: A Case Study With Phaeodactylum Tricornutum, Chia-Ying Chuang, Peter H. Santschi, Chen Xu, Yuelu Jiang, Yi-Fang Ho, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

In order to investigate the importance of biogenic silica associated biopolymers on the scavenging of radionuclides, the diatom Phaeodactylum tricornutum was incubated together with the radionuclides Th-234, Pa-233, Pb-210, and Be-7 during their growth phase. Normalized affinity coefficients were determined for the radionuclides bound with different organic compound classes (i.e., proteins, total carbohydrates, uronic acids) in extracellular (nonattached and attached exopolymeric substances), intracellular (ethylene diamine tetraacetic acid and sodium dodecyl sulfate extractable), and frustule embedded biopolymeric fractions (BF). Results indicated that radionuclides were mostly concentrated in frustule BF. Among three measured organic components, Uronic acids showed the strongest affinities to …

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Wavelength Dependent Specific Plasmon Resonance Coupling Of Single Silver Nanoparticles With Egfp, Kerry J. Lee, Tao Huang, Prakash D. Nallathamby Jan 2015

Wavelength Dependent Specific Plasmon Resonance Coupling Of Single Silver Nanoparticles With Egfp, Kerry J. Lee, Tao Huang, Prakash D. Nallathamby

Chemistry & Biochemistry Faculty Publications

Noble metal nanoparticles (NPs) possess unique plasmonic properties, enabling them to serve as sub-diffraction light sources and nano-antennae for a wide range of applications. Here we report the specific interaction of single Ag NPs with single EGFP molecules and a high dependence of their interaction upon localized-surface-plasmon-resonance (LSPR) spectra of single Ag NPs and EGFP. The LSPR spectra of single red Ag NPs show a stunning 60 nm blue-shift during their incubation with EGFP, whereas they remain unchanged during their incubation with bovine serum albumin (BSA). Interestingly, the peak wavelengths of the LSPR spectra of green and blue Ag NPs …

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Long-Term Litter Decomposition Controlled By Manganese Redox Cycling, Marco Keiluweit, Peter Nico, Mark E. Harmon, Jingdong Mao, Jennifer Pett-Ridge, Markus Kleber Jan 2015

Long-Term Litter Decomposition Controlled By Manganese Redox Cycling, Marco Keiluweit, Peter Nico, Mark E. Harmon, Jingdong Mao, Jennifer Pett-Ridge, Markus Kleber

Chemistry & Biochemistry Faculty Publications

Litter decomposition is a keystone ecosystem process impacting nutrient cycling and productivity, soil properties, and the terrestrial carbon (C) balance, but the factors regulating decomposition rate are still poorly understood. Traditional models assume that the rate is controlled by litter quality, relying on parameters such as lignin content as predictors. However, a strong correlation has been observed between the manganese (Mn) content of litter and decomposition rates across a variety of forest ecosystems. Here, we show that long-term litter decomposition in forest ecosystems is tightly coupled to Mn redox cycling. Over 7 years of litter decomposition, microbial transformation of litter …

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Characterization And Photodegradation Of Dissolved Organic Matter (Dom) From A Tropical Lake And Its Dominant Primary Producer, The Cyanobacteria Microcystis Aeruginosa, Thais B. Bittar, Aron Stubbins, Armando A. H. Vieira, Kenneth Mopper Jan 2015

Characterization And Photodegradation Of Dissolved Organic Matter (Dom) From A Tropical Lake And Its Dominant Primary Producer, The Cyanobacteria Microcystis Aeruginosa, Thais B. Bittar, Aron Stubbins, Armando A. H. Vieira, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

This study investigates optical and high-resolution molecular signatures and photochemical degradation of DOM from the Barra Bonita Reservoir (BB-DOM), a tropical eutrophic lake, as well as from its dominant phytoplankton species, the cyanobacteria Microcystis aeruginosa (Microcystis-DOM). Consistent with a predominantly autotrophic source, BB-DOM and Microcystis-DOM exhibited high protein-like fluorescence and contained a large number of aliphatics. Microcystis-DOM was enriched in peptide-like formulae, while BB-DOM had higher chromophoric and fluorescent DOM(CDOM and FDOM) and was enriched in moderately unsaturated formulae, indicating additions of terrigenous DOM and/or in situ processing of autochthonous material in the lake. Consistent with …

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Spectroscopic Characterization Of Oceanic Dissolved Organic Matter Isolated By Reverse Osmosis Coupled With Electrodialysis, John R. Helms, Jingdong Mao, Hongmei Chen, E. Michael Perdue, Nelson W. Green, Patrick G. Hatcher, Kenneth Mopper, Aron Stubbins Jan 2015

Spectroscopic Characterization Of Oceanic Dissolved Organic Matter Isolated By Reverse Osmosis Coupled With Electrodialysis, John R. Helms, Jingdong Mao, Hongmei Chen, E. Michael Perdue, Nelson W. Green, Patrick G. Hatcher, Kenneth Mopper, Aron Stubbins

Chemistry & Biochemistry Faculty Publications

Oceanic dissolved organic matter (DOM) is one of the largest pools of reduced carbon on Earth, yet DOM remains poorly chemically characterized. Studies to determine the chemical nature of oceanic DOM have been impeded by the lack of efficient and non-fractioning methods to recover oceanic DOM. Here, a DOM fraction (~40 to 86% recovery) was isolated using reverse osmosis/electrodialysis (RO/ED) and analyzed by solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Samples were obtained from biogeochemically distinct environments: photobleached surface gyre, productive coastal upwelling zone, oxygen minimum, North Atlantic Deep Water, and North Pacific Deep Water. A ubiquitous ‘background’ refractory …

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Note: Improved Line Strengths Of Rovibrational And Rotational Transitions Within The X3Σ⁻ Ground State Of Nh, James S.A. Brooke, Peter F. Bernath, Colin M. Western Jan 2015

Note: Improved Line Strengths Of Rovibrational And Rotational Transitions Within The X3Σ⁻ Ground State Of Nh, James S.A. Brooke, Peter F. Bernath, Colin M. Western

Chemistry & Biochemistry Faculty Publications

Recently, a line list including positions and transition strengths was published for the NH X3Σ− rovibrational and rotational transitions. The calculation of the transition strengths requires a conversion of transition matrix elements from Hund’s case (b) to (a). The method of this conversion has recently been improved during other work on the OH X2Π rovibrational transitions, by removing an approximation that was present previously. The adjusted method has been applied to the NH line list, resulting in more accurate transition strengths. An updated line list is presented that contains all possible transitions with v′ and …

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Software Puzzle: A Countermeasure To Resource-Inflated Denial-Of-Service Attacks, Yongdong Wu, Zhigang Zhao, Bao Feng, Robert H. Deng Jan 2015

Software Puzzle: A Countermeasure To Resource-Inflated Denial-Of-Service Attacks, Yongdong Wu, Zhigang Zhao, Bao Feng, Robert H. Deng

Research Collection School Of Computing and Information Systems

Denial-of-service (DoS) and distributed DoS (DDoS) are among the major threats to cyber-security, and client puzzle, which demands a client to perform computationally expensive operations before being granted services from a server, is a well-known countermeasure to them. However, an attacker can inflate its capability of DoS/DDoS attacks with fast puzzle-solving software and/or built-in graphics processing unit (GPU) hardware to significantly weaken the effectiveness of client puzzles. In this paper, we study how to prevent DoS/DDoS attackers from inflating their puzzle-solving capabilities. To this end, we introduce a new client puzzle referred to as software puzzle. Unlike the existing client …

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Electrochemical Monitoring Of The Interaction Between Mitomycin C And Dna At Chitosan--Carbon Nanotube Composite Modified Electrodes, Pembe Ece Canavar, Ece Ekşi̇n, Kadri̇ye Arzum Erdem Gürsan Jan 2015

Electrochemical Monitoring Of The Interaction Between Mitomycin C And Dna At Chitosan--Carbon Nanotube Composite Modified Electrodes, Pembe Ece Canavar, Ece Ekşi̇n, Kadri̇ye Arzum Erdem Gürsan

Turkish Journal of Chemistry

Single-walled carbon nanotube (CNT) and chitosan composite (chitosan*CNT) based sensors were developed as DNA biosensors, and then they were applied for electrochemical investigation of the interaction between the anticancer drug mitomycin C (MC) and DNA. The oxidation signals of MC and guanine were monitored before and after the interaction process by differential pulse voltammetry (DPV). The DPV results were in good agreement with those of electrochemical impedance spectroscopy (EIS). Analytical parameters such as DNA concentration, MC concentration, and MC interaction time with DNA were optimized. The detection limits were 6.85 \mu g/mL for DNA and 11.01 \mu g/mL for MC.

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Kinetics And Performance Studies Of A Switchable Solvent Tmg (1,1,3,3-Tetramethylguanidine)/1-Propanol/Carbon Dioxide System, Özge Yüksel, Mustafa Çağdaş Öztürk, Ayça Şeker, Erdoğan Alper Jan 2015

Kinetics And Performance Studies Of A Switchable Solvent Tmg (1,1,3,3-Tetramethylguanidine)/1-Propanol/Carbon Dioxide System, Özge Yüksel, Mustafa Çağdaş Öztürk, Ayça Şeker, Erdoğan Alper

Turkish Journal of Chemistry

The rate constants and the activation energies of the reaction between carbon dioxide and 1,1,3,3-tetramethylguanidine (TMG) in 1-propanol solution were measured by a stopped-flow technique at a temperature range of 288--308 K and at a TMG concentration range of 2.5--10.0 wt %. Based on the pseudo-first-order reaction for CO_2, the reaction was modeled by a termolecular reaction mechanism, which resulted in a rate constant of 199.30 m^3 kmol^{-1} s^{-1} at 298 K. The activation energies were 5.19 kJ/mol and 5.26 kJ/mol at 2.5 and 5.0 wt % TMG, respectively. In addition, carbon dioxide absorption capacity was investigated using a gas--liquid …

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Dual Effect Of Coumarin Benzimidazolium Ionic Salt Covalently Bonded On A Silica Network, Ahmet Gültek, Davut Aksüt, Turgay Seçki̇n, Emre Bi̇rhanli, Mert Olgun Karataş, Bülent Alici Jan 2015

Dual Effect Of Coumarin Benzimidazolium Ionic Salt Covalently Bonded On A Silica Network, Ahmet Gültek, Davut Aksüt, Turgay Seçki̇n, Emre Bi̇rhanli, Mert Olgun Karataş, Bülent Alici

Turkish Journal of Chemistry

Synthesis of the ionic liquid 1-allyl-3-(4-methyl-7,8-dihydroxy-2H-chromen-2-one) benzimidazolium chloride followed by the conversion of ammonium salts on the imidazole ring hooked to the coumarin group was modified by postmodification of the silica matrix where 3-chloropropyltrimethoxysilane was used as not only a surface modification agent, but also as an ATRP halogen source. The synergetic effect of charged ammonium groups as well as hydroxyl groups present on the coumarin was investigated in terms of ATRP polymerization. The results confirmed that brush polymers show outstanding antibacterial effects against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa.

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Synthesis And Evaluation Of Antioxidant Activities Of Novel 1,3,4-Oxadiazole And Imine Containing 1h-Benzimidazoles, Ayşe Selen Alp, Gülgün Kilcigi̇l, Elçi̇n Deni̇z Özdamar, Tülay Çoban, Bi̇nay Eke Jan 2015

Synthesis And Evaluation Of Antioxidant Activities Of Novel 1,3,4-Oxadiazole And Imine Containing 1h-Benzimidazoles, Ayşe Selen Alp, Gülgün Kilcigi̇l, Elçi̇n Deni̇z Özdamar, Tülay Çoban, Bi̇nay Eke

Turkish Journal of Chemistry

Some novel 2-(substitutedbenzylthio)-5-((2-(4-substitutedphenyl)-1H-benzo[d]imidazol-1-yl)methyl)-1,3,4-oxadiazoles (5--12) and 2-(2-(4-chlorophenyl)-1H-benzo[d]imidazol-1-yl)-N'-(arylmethylene)acetohydrazide derivatives (13--22) were prepared and their in vitro antioxidant properties were investigated by determination of rat liver microsomal NADPH-dependent inhibition of lipid peroxidation (LP) levels and microsomal ethoxyresorufin O-deethylase (EROD) activity. Compound 18 was found to be the most active compound with 100% inhibition on LP level and 92% inhibition on EROD. Compounds 4b, 17, and 19 showed the strongest inhibitory effect (97%) on EROD. The free radical scavenging capacities of the compounds were also tested in vitro determining the interaction of the stable free radical 2,2,diphenyl-1-picrylhydrazyl (DPPH), and compounds 4a and 4b exhibited …

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Reduction Behavior Of Fenoxaprop-P-Ethyl And Its Voltammetric Determination, Zeki̇ Eş, İbrahi̇m Hüdai̇ Taşdemi̇r Jan 2015

Reduction Behavior Of Fenoxaprop-P-Ethyl And Its Voltammetric Determination, Zeki̇ Eş, İbrahi̇m Hüdai̇ Taşdemi̇r

Turkish Journal of Chemistry

The reduction behavior of fenoxaprop-p-ethyl (FNX) was studied on a hanging mercury drop electrode. FNX showed 2 reduction peaks at about --0.7 V and at about --0.9 V versus Ag/AgCl/3.0 M KCl in Britton--Robinson buffer at pH 4.8. Both reductions were irreversible and adsorption was effective. The reduction peaks were assigned to the reduction of C=N to CH--NH and the reduction of C=O to CH--OH. Square-wave voltammetry has been proposed and validated for quantification of FNX in different samples. The linear working range was established as 0.30--15.0 \mu M. Limit of detection and limit of quantification were calculated as 0.07 …

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Effect Of Acrylic Acid Feed Contents Of Microgels On Catalytic Activity Of Silver Nanoparticles Fabricated Hybrid Microgels, Zahoor Hussain Farooqi, Shanza Rauf Khan, Robina Begum, Farah Kanwal, Ahsan Sharif, Ejaz Ahmed, Shumaila Majeed, Kiran Ejaz, Aysha Ijaz Jan 2015

Effect Of Acrylic Acid Feed Contents Of Microgels On Catalytic Activity Of Silver Nanoparticles Fabricated Hybrid Microgels, Zahoor Hussain Farooqi, Shanza Rauf Khan, Robina Begum, Farah Kanwal, Ahsan Sharif, Ejaz Ahmed, Shumaila Majeed, Kiran Ejaz, Aysha Ijaz

Turkish Journal of Chemistry

We synthesized poly(N-isopropylacrylamide-co-acrylic acid) microgels with 1, 3, 5, and 7 mol percentage of acrylic acid. Silver nanoparticles were fabricated inside these microgels at room temperature. Pure microgels were characterized by Fourier transform infrared (FTIR) spectroscopy and dynamic light scattering (DLS). Hybrid microgels were characterized by UV-Visible spectroscopy. The size of the silver nanoparticles increased with an increase in the content of acrylic acid. Catalytic activity of these hybrid microgels was investigated using UV-Visible spectrophotometry. Induction time decreased from 8.8 to 2.6 min and the value of apparent rate constant decreased from 0.226 to 0.109 min^{-1}, when the content of …

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Synthesis Of Tetrahydropyrimidinium Salts And Their In Situ Catalytic Activities Towards The Buchwald--Hartwig Amination Reaction Under Microwave Irradiation, Liangru Yang, Huanyu Bian, Wenpeng Mai, Pu Mao, Yongmei Xiao, Dong Wei, Lingbo Qu Jan 2015

Synthesis Of Tetrahydropyrimidinium Salts And Their In Situ Catalytic Activities Towards The Buchwald--Hartwig Amination Reaction Under Microwave Irradiation, Liangru Yang, Huanyu Bian, Wenpeng Mai, Pu Mao, Yongmei Xiao, Dong Wei, Lingbo Qu

Turkish Journal of Chemistry

A series of asymmetrical substituted tetrahydropyrimidinium salts and different kinds of bridged bis-tetrahydropyrimidinium salts were prepared through the quaterization of tetrahydropyrimidine or the dehydrogenation of hexahydropyrimidine. They were characterized and used as NHC precursors in the palladium catalyzed Buchwald--Hartwig amination reaction. The in situ formed catalytic system Pd(OAc)_2/tetrahydropyrimidinium and ^tBuOK catalyzed the amination of heteroaryl halides and heterocyclic amines effectively, producing the heterocyclic amine functionalized heteroaryl derivatives in high yields.

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Synthesis And Properties Of Novel Magnetic Nanoparticles Grafted With Nitropyridine-Substituted Calix[4]Arene Derivative As Cr^{6+} Extractant, Serkan Sayin, Vi̇ldan Doğan Jan 2015

Synthesis And Properties Of Novel Magnetic Nanoparticles Grafted With Nitropyridine-Substituted Calix[4]Arene Derivative As Cr^{6+} Extractant, Serkan Sayin, Vi̇ldan Doğan

Turkish Journal of Chemistry

A new calix[4]arene derivative, 3, which functionalized at the lower rim with 2-(2-aminoethyl amino)-5-nitropyridine, was synthesized and characterized by a combination of FTIR, ^1H NMR, ^{13}C NMR, and elemental analysis. Then the calix[4]arene 3 was grafted onto [3-(2,3-epoxypropoxy)propyl]trimethoxysilane-modified Fe_3O_4-- nanoparticles (EPPTMS-MN) to produce new calixarene-adorned magnetic nanoparticles (MN-DiNoPy-Calix (4)). The structure of the calixarene-adorned magnetic nanoparticles 4 was determined by a combination of FTIR, TEM, and elemental analysis. Moreover, a study regarding the removal of toxic HCr_2O_7^- anion from aqueous solution was also carried out with the calixarene-adorned magnetic nanoparticles in solid--liquid extraction studies.

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Synthesis, Properties, And Electrochemistry Of A Photochromic Compound Based On Dithienylethene And Prodot, Melek Pamuk Algi, Ati̇lla Ci̇haner, Fati̇h Algi Jan 2015

Synthesis, Properties, And Electrochemistry Of A Photochromic Compound Based On Dithienylethene And Prodot, Melek Pamuk Algi, Ati̇lla Ci̇haner, Fati̇h Algi

Turkish Journal of Chemistry

The synthesis, photochromic features, and electrochemistry of a novel material based on dithienylethene (DTE) and 3,3-didecyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine (didecyl-ProDOT) units are described. It is noteworthy that 1,2-bis(5-(3,3-didecyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-6-yl)-2-methylthiophen-3-yl)cyclopent-1-ene can be efficiently switched between open and closed states by light in both solution and in the solid poly(methyl metacrylate) (PMMA) matrix. It is also found that the emission of this novel compound can be switched on and off upon irradiation.

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Preparation Of Visible Light Sensitive Nano-Sized N-Tio_2 Photocatalysts And Their Photocatalytic Activity Under Visible Light, Young-Gu Kang, Kwang-Hyeok Lee, Hyun-Sik Hahm Jan 2015

Preparation Of Visible Light Sensitive Nano-Sized N-Tio_2 Photocatalysts And Their Photocatalytic Activity Under Visible Light, Young-Gu Kang, Kwang-Hyeok Lee, Hyun-Sik Hahm

Turkish Journal of Chemistry

This study aimed to develop a photocatalyst that responds to visible light. For the preparation of visible light sensitive photocatalysts, N was doped into TiO_2 (N-TiO_2). To inhibit the recombination of excited electrons and holes, transition metals (M = Pt, Cu, Fe, Cr) were loaded on the N-TiO_2. N-TiO_2 nanotubes were also synthesized by a hydrothermal treatment of the prepared N-TiO_2 in a strong basic environment. The prepared photocatalysts were characterized by XRD, FESEM, HRTEM, XPS, and UV/VIS spectrophotometer, and their photocatalytic activity was tested by the photodecomposition of liquid-phase methylene blue and gas-phase acetone.

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Deposition Of Cadmium Sulfide And Zinc Sulfide Thin Films By Aerosol-Assisted Chemical Vapors From Molecular Precursors, Ashfaque Ahmed Memon, Malik Dilshad, Neerish Revaprasadu, Muhammad Azad Malik, James Raftery, Javeed Akhtar Jan 2015

Deposition Of Cadmium Sulfide And Zinc Sulfide Thin Films By Aerosol-Assisted Chemical Vapors From Molecular Precursors, Ashfaque Ahmed Memon, Malik Dilshad, Neerish Revaprasadu, Muhammad Azad Malik, James Raftery, Javeed Akhtar

Turkish Journal of Chemistry

New complexes with the general formula [M(S_2CN^nBu_2)_2] [where M = Cd^{II} (1) and Zn^{II} (2)] were synthesized and used as single source precursors to deposit thin films of cadmium sulfide and zinc sulfide by the aerosol-assisted chemical vapor deposition technique. The single crystal X-ray structures of 1 and 2 are also reported. Thermogravimetric analysis of 1 and 2 showed that both precursors decompose cleanly in a single step to produce their respective metal sulfides. The deposition of thin films was carried out on soda glass substrates in the 350--450 °C temperature range under inert conditions. The as-deposited thin films were …

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Synthesis, Molecular Docking, And Antitumoral Activity Of Alnustone-Like Compounds Against Estrogen Receptor Alpha-Positive Human Breast Cancer, Kaan Küçükoğlu, Hati̇ce Seçi̇nti̇, Aykut Özgür, Hasan Seçen, Yusuf Tutar Jan 2015

Synthesis, Molecular Docking, And Antitumoral Activity Of Alnustone-Like Compounds Against Estrogen Receptor Alpha-Positive Human Breast Cancer, Kaan Küçükoğlu, Hati̇ce Seçi̇nti̇, Aykut Özgür, Hasan Seçen, Yusuf Tutar

Turkish Journal of Chemistry

Alnustone-like compounds are promising inhibitors for estrogen receptor \alpha (ER-\alpha), which is a novel cancer therapeutic target. Therefore, 10 alnustone-like compounds with substituents at the phenyl rings were synthesized by condensation of 4-phenyl-2-butanones and cinnamaldehydes via in situ enamination. The compounds displayed either protective activity or inhibited cell growth and proliferation of human breast cancer cells. Molecular docking studies indicated that the synthesized compounds interact with ER-\alpha efficiently. In this work, the protective and inhibitive roles of the synthesized compounds were related to their functional groups and to their binding mode of action on ER-\alpha protein. The compounds are potential …

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Fluorescent Mono- And Tetra-Dansylated Cavitands: Synthesis And Acid Sensitivity, Ümi̇t İşci̇, Yunus Zorlu, Fabienne Dumoulin Jan 2015

Fluorescent Mono- And Tetra-Dansylated Cavitands: Synthesis And Acid Sensitivity, Ümi̇t İşci̇, Yunus Zorlu, Fabienne Dumoulin

Turkish Journal of Chemistry

Two fluorescent tetra- and mono-dansylated resorcinarene cavitands were prepared and fully characterized. The X-ray structure of mono-dansylated resorcinarene cavitand was obtained. Their intrinsic absorption and fluorescence properties were studied. These properties were strongly sensitive to the presence of perchloric acid, as evidenced by the appearance of isobestic points upon protonation of the dansyl dimethylamino functions. The decreasing of the fluorescence emission intensity upon titration with perchloric acid was explained by the excited state interactions between the dansyl groups of the resorcinarene. Fluorescence quantum yields (\Phi _F) of mono- and tetra-dansylated cavitands and the reference compound were determined using dansyl chloride …

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A Green Light Emitting Polymer In A Pmma Matrix: Oligo(Azomethine-Ether) With Benzothiazole Moieties, Mehmet Yildirim, İsmet Kaya Jan 2015

A Green Light Emitting Polymer In A Pmma Matrix: Oligo(Azomethine-Ether) With Benzothiazole Moieties, Mehmet Yildirim, İsmet Kaya

Turkish Journal of Chemistry

This study aimed to synthesize an oligo(azomethine-ether) with benzothiazole moiety in organic medium by means of chemical oxidative polycondensation (OP). Optical properties were examined by photoluminescence (PL) and UV-Vis measurements both in solutions and solid film involved a poly (methyl methacrylate) (PMMA) matrix. Oligomer film in the PMMA matrix emitted a fine green light with a fluorescence quantum yield (QY) of 3.30%. Spectral and thermal observations showed a high rate of C--O--C coupling (cross-linking) for the oligomer. SEC results indicated low molecular weight (\sim3200--4650 g mol^{-1}) and the oligomer was soluble in organic solvents with high polarity. Electrochemical behavior was …

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Synthesis Of New Oxindole Derivatives Containing Benzothiazole And Thiazolidinone Moieties Using Nano Silica-Bonded 5-N-Propyl-Octahydro-Pyrimido[1,2-A]Azepinium Chloride (Nsb-Dbu) As Catalyst, Robabeh Baharfar, Narges Shariati Jan 2015

Synthesis Of New Oxindole Derivatives Containing Benzothiazole And Thiazolidinone Moieties Using Nano Silica-Bonded 5-N-Propyl-Octahydro-Pyrimido[1,2-A]Azepinium Chloride (Nsb-Dbu) As Catalyst, Robabeh Baharfar, Narges Shariati

Turkish Journal of Chemistry

A facile one-pot synthesis of novel oxindole derivatives bearing benzothiazolylmethyl-2-thioxothiazolidin-4-one was accomplished via one-pot reaction of 5-oxoindolinylidene rhodanine-3-acetic acid derivatives, 2-aminothiophenol, and triphenyl phosphite in the presence of tetrabutylammonium bromide (TBAB) and nano silica-bonded 5-n-propyl-octahydro-pyrimido[1,2-a]azepinium chloride (NSB-DBU) as heterogeneous reusable nanocatalyst. The target compounds were obtained in excellent yields (85%--92%) and short reaction times under fairly mild reaction conditions.

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Regiospecific One-Pot, Combinatorial Synthesis Of New Substituted Pyrimido[4,5-C]Pyridazines As Potential Monoamine Oxidase Inhibitors, Mehdi Rimaz, Paria Pourhossein, Behzad Khalili Jan 2015

Regiospecific One-Pot, Combinatorial Synthesis Of New Substituted Pyrimido[4,5-C]Pyridazines As Potential Monoamine Oxidase Inhibitors, Mehdi Rimaz, Paria Pourhossein, Behzad Khalili

Turkish Journal of Chemistry

New 3-aryl-6-methylpyrimido[4,5-c]pyridazine-5,7(6H,8H)-diones and 3-aryl-6-ethyl-7-thioxo-7,8-dihydropyrimido[4,5-c]pyridazin-5(6H)-ones were efficiently synthesized via a regiospecific one-pot reaction of N-methylbarbituric acid and N-ethyl-2-thiobarbituric acid with various arylglyoxal monohydrates in the presence of hydrazine dihydrochloride in ethanol at 50 °C. The target compounds were obtained in high yields and were regioisomerically pure after recrystallization. These new heterocycles may act as potential MAO_{B} inhibitors.

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Revisiting The Biodesulfurization Capability Of Hyperthermophilic Archaeon Sulfolobus Solfataricus P2 Revealed Dbt Consumption By The Organism In An Oil/Water Two-Phase Liquid System At High Temperatures, Gökhan Gün, Yuda Yürüm, Gi̇zem Di̇nler Doğanay Jan 2015

Revisiting The Biodesulfurization Capability Of Hyperthermophilic Archaeon Sulfolobus Solfataricus P2 Revealed Dbt Consumption By The Organism In An Oil/Water Two-Phase Liquid System At High Temperatures, Gökhan Gün, Yuda Yürüm, Gi̇zem Di̇nler Doğanay

Turkish Journal of Chemistry

The ability of the hyperthermophilic archaeon Sulfolobus solfataricus P2 to grow on organic and inorganic sulfur sources was investigated. A sulfur-free mineral medium was employed with different sources of carbon. The results showed that inorganic sulfur sources display growth curve patterns significantly different from the curves obtained with organic sulfur sources. Solfataricus has the ability to utilize DBT and its derivatives, but it lacks BT utilization. Solfataricus} utilizes DBT at a rate of 1.23 \mu mol 2-HBP h^{-1} g DCW^{-1} even at 78 °C, at which DBT is known to be unstable. After enabling DBT stabilization using a two-phase culture …

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Pfam Catalyzed Enantioselective Diethylzinc Addition To Imines, Özdemi̇r Doğan, Eda Çağli Jan 2015

Pfam Catalyzed Enantioselective Diethylzinc Addition To Imines, Özdemi̇r Doğan, Eda Çağli

Turkish Journal of Chemistry

Chiral amines are important starting materials for the synthesis of biologically important compounds. Enantioselective addition of dialkylzinc reagents to imines is a reliable method for the synthesis of these compounds. Different chiral catalysts were developed and used for this method. Phosphorous based PFAM catalysts were tried for the first time in the enantioselective synthesis of amines by reacting diethylzinc with N-sulfonyl imines and N-diphenylphosphinoyl imines. Chiral amines were isolated with moderate to acceptable yields and enantioselectivities.

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Effect Of Sonic Treatment On The Permeation Performance Of Cellulose Acetate Membranes Modified By N-Sio_2, Gülsen Asman, Mürvet Kaya, Nursel Pekel Bayramgi̇l Jan 2015

Effect Of Sonic Treatment On The Permeation Performance Of Cellulose Acetate Membranes Modified By N-Sio_2, Gülsen Asman, Mürvet Kaya, Nursel Pekel Bayramgi̇l

Turkish Journal of Chemistry

Cellulose acetate (CA) membranes were modified by nano-silicon dioxide (n-SiO_2), and they were exposed to ultrasonic waves at a frequency of 35 kHz. The effect of sonication on their water sorption tendency and permeation capability was investigated. The characterization of the membranes was done by FTIR and SEM analysis, and the hydrophilic character of the membranes was deduced by swelling studies and contact angle (CAn) measurements. Permeation studies of the membranes were performed by using the diffusion method and theophylline was used as a model chemical in the permeation studies. The results indicated that beside the high hygroscopic property of …

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Molecular Docking Analysis And Molecular Dynamics Simulation Study Of Ameltolide Analogous As A Sodium Channel Blocker, Maryam Iman, Atefeh Saadabadi, Asghar Davood Jan 2015

Molecular Docking Analysis And Molecular Dynamics Simulation Study Of Ameltolide Analogous As A Sodium Channel Blocker, Maryam Iman, Atefeh Saadabadi, Asghar Davood

Turkish Journal of Chemistry

Fifteen compounds related to ameltolide with sodium channel inhibitory activity were subjected to a molecular docking study. The chemical structures of all compounds were built using the program HyperChem and conformational studies were performed with a semiempirical method followed by the PM3 method. A docking study was performed using the program AutoDock on all the compounds. To confirm the binding mode of inhibitors, molecular dynamics simulations were performed using GROMACS 4.5.5, based upon the docked conformation of ameltolide. The docking analyses indicated that these compounds interacted mainly with residues II-S6 and III-S6 of NaV1.2 by making hydrogen bonds and (\pi …

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Improvement Of Solubility Of Celecoxib By Inclusion In Mcm-41 Mesoporous Silica: Drug Loading And Release, Şahi̇ka Günaydin, Ayşen Yilmaz Jan 2015

Improvement Of Solubility Of Celecoxib By Inclusion In Mcm-41 Mesoporous Silica: Drug Loading And Release, Şahi̇ka Günaydin, Ayşen Yilmaz

Turkish Journal of Chemistry

Celecoxib is a poorly water-soluble nonsteroidal anti-inflammatory drug. Here we report four ordered mesoporous silica MCM-41 supports with different particle size, pore volume, and surface properties to investigate their loading capacity with celecoxib and their release abilities. Spherical MCM-41 mesoporous supports less than 50 nm in diameter were prepared and to compare the effect of the template removal process on morphology of samples, acid extraction and calcination methods were used. Moreover, nearly 500 nm sized rod-shaped MCM-41 mesoporous silica was obtained by changing the template concentration in preparation. Boron doping was performed to determine the effect of a heteroatom on …

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