Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Physical Sciences and Mathematics (11098)
- Education (3523)
- Engineering (3037)
- Computer Sciences (2765)
- Social and Behavioral Sciences (2259)
-
- Environmental Sciences (1899)
- Life Sciences (1891)
- Chemistry (1499)
- Physics (1467)
- Mathematics (1334)
- Arts and Humanities (1243)
- Earth Sciences (1124)
- Medicine and Health Sciences (1095)
- Electrical and Computer Engineering (960)
- Computer Engineering (804)
- Higher Education (797)
- Science and Mathematics Education (700)
- Law (657)
- Business (632)
- Statistics and Probability (628)
- Oceanography and Atmospheric Sciences and Meteorology (595)
- Curriculum and Instruction (540)
- Teacher Education and Professional Development (512)
- Geology (437)
- Educational Assessment, Evaluation, and Research (435)
- Mechanical Engineering (428)
- Natural Resources and Conservation (428)
- Applied Mathematics (417)
- Sustainability (407)
- Astrophysics and Astronomy (394)
- Institution
-
- University of Nebraska - Lincoln (881)
- TÜBİTAK (719)
- University of Kentucky (530)
- Singapore Management University (522)
- Utah State University (484)
-
- University of South Florida (412)
- Louisiana State University (370)
- Old Dominion University (369)
- Rose-Hulman Institute of Technology (365)
- University of Plymouth (358)
- City University of New York (CUNY) (355)
- University of New Mexico (355)
- Chulalongkorn University (349)
- Portland State University (347)
- Missouri University of Science and Technology (324)
- Nova Southeastern University (308)
- Walden University (307)
- Georgia Southern University (301)
- Purdue University (285)
- Brigham Young University (263)
- Technological University Dublin (261)
- University of South Carolina (255)
- Association of Arab Universities (254)
- University of Nevada, Las Vegas (232)
- Embry-Riddle Aeronautical University (231)
- Wright State University (227)
- University of Arkansas, Fayetteville (220)
- San Jose State University (218)
- University of Texas at El Paso (206)
- University of Central Florida (204)
- Keyword
-
- Education (263)
- Mathematics (218)
- STEM (111)
- Curriculum (98)
- Machine learning (98)
-
- Climate change (97)
- Physics (96)
- Northern bobwhite (88)
- Colinus virginianus (85)
- Optimization (82)
- Georgia Southern University (81)
- Technology (80)
- Higher education (79)
- Sustainability (79)
- Simulation (77)
- Assessment (76)
- Humans (72)
- Science (69)
- Literacy (65)
- Gender (64)
- Engineering (62)
- Modeling (62)
- Motivation (57)
- Chemistry (56)
- Machine Learning (55)
- Environmental science (53)
- Science education (53)
- Professional development (52)
- Statistics (51)
- Calculus (49)
- Publication
-
- Theses and Dissertations (948)
- Electronic Theses and Dissertations (492)
- Research Collection School Of Computing and Information Systems (427)
- Faculty Publications (396)
- Turkish Journal of Electrical Engineering and Computer Sciences (389)
-
- Rose-Hulman Undergraduate Mathematics Journal (350)
- Chulalongkorn University Theses and Dissertations (Chula ETD) (313)
- Dissertations (304)
- Walden Dissertations and Doctoral Studies (297)
- School of Engineering, Computing and Mathematics (220)
- USF Tampa Graduate Theses and Dissertations (207)
- Applied Mathematics & Information Sciences (203)
- Theses (185)
- Doctoral Dissertations (181)
- Publications and Research (176)
- Publications (174)
- Articles (146)
- Turkish Journal of Mathematics (140)
- Honors Theses (136)
- Browse all Theses and Dissertations (135)
- Graduate Theses and Dissertations (130)
- Open Access Dissertations (122)
- New Mexico Quarterly (112)
- Masters Theses (111)
- National Quail Symposium Proceedings (111)
- Undergraduate Student Symposium (110)
- Defensive Publications Series (105)
- Dissertations, Theses, and Capstone Projects (105)
- All Graduate Theses and Dissertations, Spring 1920 to Summer 2023 (104)
- LSU Doctoral Dissertations (104)
- Publication Type
Articles 23671 - 23700 of 24666
Full-Text Articles in Entire DC Network
The Structure And Cytotoxic Activity Of A New Saponin: Cephoside A From Cephalaria Elazigensis Var. Purpurea, Peyker Kayce, Nazli Boke Sarikahya, Murat Pekmez, Nazli Arda, Suheyla Kirmizigul
The Structure And Cytotoxic Activity Of A New Saponin: Cephoside A From Cephalaria Elazigensis Var. Purpurea, Peyker Kayce, Nazli Boke Sarikahya, Murat Pekmez, Nazli Arda, Suheyla Kirmizigul
Turkish Journal of Chemistry
Investigation of the aerial parts of Cephalaria elazigensis var. purpurea afforded one new oleanane-type saponin, namely cephoside A (1), and five known natural compounds (2-6). Compound 2, named anemoclemoside A, which is an unusual triterpene glycoside, was identified in the family Dipsacaceae for the first time. Chemical structures of all compounds were determined on the basis of the HRESIMS and 1D and 2D NMR data. Cephoside A (1) and anemoclemoside A (2) were assessed for their cytotoxic activities against HeLa cells, having IC$_{50}$ values of 495 and 135 $\mu $g/mL, respectively.
Stereoselective And Regioselective Synthesis Of $N$-Substituted Methyl 2-((Azolyl)Methyl)-3-Arylacrylates From Baylis-Hillman Acetates, Ayşen Köseceli̇ Özenç, İlhami̇ Çeli̇k, Şule Kökten
Stereoselective And Regioselective Synthesis Of $N$-Substituted Methyl 2-((Azolyl)Methyl)-3-Arylacrylates From Baylis-Hillman Acetates, Ayşen Köseceli̇ Özenç, İlhami̇ Çeli̇k, Şule Kökten
Turkish Journal of Chemistry
$N$-Substituted methyl 2-((azolyl)methyl)-3-arylacrylates were synthesized stereo- and regioselectively with one-pot reaction between Baylis--Hillman acetates and a suitable acylazole in the presence of K$_{2}$CO$_{3}$ as a base catalyst. The targeted $N$-substituted azole acrylates were efficiently obtained in good yields (39%-89%).
Fabrication Of Multilayer Graphene Oxide-Reinforced High Density Polyethylene Nanocomposites With Enhanced Thermal And Mechanical Properties Via Thermokinetic Mixing, Burcu Saner Okan
Turkish Journal of Chemistry
High density polyethylene (HDPE) was compounded with thermally exfoliated graphene oxide (TEGO) by thermokinetic mixing in a short time. High shear rates during the compounding process provided high exfoliation and proper dispersion of graphene layers in the polymer matrix. Different TEGO/polymer ratios were used to get efficient melt mixing. Structural analysis by spectroscopic techniques confirmed the exfoliation of TEGO sheets and the coverage of their surfaces by HDPE chains. Furthermore, homogeneous dispersion of graphene sheets in the matrix led to the enhancement in the mechanical and thermal properties of HPDE-based nanocomposites. Especially stress concentration sites were significantly reduced by preventing …
Dehydration Behavior And Kinetics Of Kurnakovite Under Microwave Irradiation, Fatma Tuğçe Şenberber, Meral Yildirim, İkli̇m Nergi̇z Özdoğan, Azmi̇ Seyhun Kipçak, Emek Derun
Dehydration Behavior And Kinetics Of Kurnakovite Under Microwave Irradiation, Fatma Tuğçe Şenberber, Meral Yildirim, İkli̇m Nergi̇z Özdoğan, Azmi̇ Seyhun Kipçak, Emek Derun
Turkish Journal of Chemistry
In this research, the dehydration behavior of kurnakovite was studied under microwave irradiation. The kinetic parameters of the dehydration reaction were determined using different kinetic models. Kurnakovite was characterized by the techniques of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) before and after the dehydration process. According to the results, kurnakovite was identified as a compound with the powder diffraction file (pdf) number 00-024-0700 before the dehydration process and after the dehydration process amorphous formations were observed. Moreover, FT-IR results showed that dehydration was completed successfully because of the disappearance in the band values …
A Biochar-Modified Carbon Paste Electrode, Derya Bal Altuntaş, Gökçen Akgül, Jale Yanik, Ülkü Anik
A Biochar-Modified Carbon Paste Electrode, Derya Bal Altuntaş, Gökçen Akgül, Jale Yanik, Ülkü Anik
Turkish Journal of Chemistry
The present work examıned the use of biochar derived from tea waste as a novel electrode material. For the fabrication of the biochar electrode, suitable amounts of biochar and graphite were mixed with mineral oil for the first time. The electrochemical performance of the biochar-modified carbon paste electrode (BCPE) was measured by various cyclic voltammetric reactions for several redox systems. The factors affecting the electrode kinetics of BCPE surfaces were examined and optimized. The BCPE was applied as transducer in a glucose biosensor. The results reflect the effective properties of composite electrodes and the electrochemical properties of biochar showing that …
A Rapid, Eco-Friendly, And Reliable Microplate Method For Determination Of Cr(Vi), Alejandro Coreño Alonso, Gustavo Cruz Jimenez, Leticia Lopez Martinez, Georgina Elena Reyna Lopez, Francisco Javier Acevedo Aguilar
A Rapid, Eco-Friendly, And Reliable Microplate Method For Determination Of Cr(Vi), Alejandro Coreño Alonso, Gustavo Cruz Jimenez, Leticia Lopez Martinez, Georgina Elena Reyna Lopez, Francisco Javier Acevedo Aguilar
Turkish Journal of Chemistry
In the present work, the reaction of Cr(VI) with 1,5-diphenylcarbazide in microplates (enzyme-linked immunosorbent assay microtiter plate) and a subsequent determination in a plate reader at 540 nm were performed. The final volume utilized for each determination was 200 $\mu $L, and the cost and waste were reduced for hexavalent chromium [Cr(VI)] quantification. The use of microplates allowed for the analysis of a large number of samples, reducing analysis time. No statistically significant differences were observed between the results obtained in the analysis of Cr(VI) in real samples by the conventional procedure and by the proposed methodology in this work …
Microwave-Enhanced Fenton-Like Degradation By Surface-Modified Metal-Organic Frameworks As A Promising Method For Removal Of Dye From Aqueous Samples, Seyed Ershad Moradi, Shayessteh Dadfarnia, Ali Mohammad Haji Shabani, Saeed Emami
Microwave-Enhanced Fenton-Like Degradation By Surface-Modified Metal-Organic Frameworks As A Promising Method For Removal Of Dye From Aqueous Samples, Seyed Ershad Moradi, Shayessteh Dadfarnia, Ali Mohammad Haji Shabani, Saeed Emami
Turkish Journal of Chemistry
In the current research, the sulfonated metal-organic framework loaded on iron oxide nanoparticles, Fe$_{3}$O$_{4}$@MIL-100(Fe)-OSO$_{3}$H, has been synthesized and utilized as a Fenton-like catalyst for the decolorization of aqueous solutions containing methyl orange (MO) dye as a model organic pollutant. The morphology and structure of the catalyst were characterized by X-ray powder diffraction, transmission electron microscopy, Brunauer-Emmett-Teller analysis, thermogravimetric analysis, Fourier transform infrared spectroscopy, and UV-Vis diffuse reflectance spectroscopy. The effects of various parameters on MO degradation were investigated and the optimum conditions for MO degradation were found to be an initial concentration of MO of 100 mg/L, initial concentration of …
Synthesis Of Na-, Fe-, And Co-Promoted Tio$_{2}$/Multiwalled Carbon Nanotube Composites And Their Use As A Photocatalyst, Alp Yürüm, Gürkan Karakaş
Synthesis Of Na-, Fe-, And Co-Promoted Tio$_{2}$/Multiwalled Carbon Nanotube Composites And Their Use As A Photocatalyst, Alp Yürüm, Gürkan Karakaş
Turkish Journal of Chemistry
The use of multiwalled carbon nanotubes (CNTs) in sol-gel synthesized titanium dioxide (TiO$_{2})$ photocatalysts as templates was systematically studied. CNTs have high oxidative thermal stability and the controlled removal of CNTs can be achieved at lower temperatures under air flow by the use of Na, Fe, and Co as a catalyst. These catalysts helped to reduce the oxidation temperature of CNTs; thus anatase phase was achieved without significant sintering. The use of a promoter, heat treatment, and various heat treatment atmospheres was effective in specific surface area, crystallinity, and photocatalytic activity against methylene blue (MB) degradation. While the specific surface …
Singlet Oxygen Generation From Poly[4-Diacetoxyiodo]Styrene And Hydrogen Peroxide, Mustafa Çatir
Singlet Oxygen Generation From Poly[4-Diacetoxyiodo]Styrene And Hydrogen Peroxide, Mustafa Çatir
Turkish Journal of Chemistry
Treatment of hydrogen peroxide with a polymer-supported hypervalent iodine compound, poly[4-diacetoxyiodo] styrene (PDAIS), generates singlet molecular oxygen ($^{1}$O$_{2})$. Singlet oxygen generation was proved by trapping with typical organic compounds such as conjugated dienes, aromatic dienes, and electron-rich alkene. When compared to monomer analogue, the use of PDAIS in peroxidation of substrates gave slightly better yields (45%-96%). Regeneration and reuse of PDAIS showed similar activity. The mechanism underlying generation of singlet oxygen and reaction scope was examined.
Synthesis Of Neodymium-Iron Nanoperovskite For Sensing Applications Of An Antiallergic Drug, Nada F. Atta, Mohammad H. Binsabt, Ekram H. El-Ads, Ahmed Galal
Synthesis Of Neodymium-Iron Nanoperovskite For Sensing Applications Of An Antiallergic Drug, Nada F. Atta, Mohammad H. Binsabt, Ekram H. El-Ads, Ahmed Galal
Turkish Journal of Chemistry
A facile route was used for the fabrication of NdFeO$_{3}$ (NF) perovskite. The orthorhombic structure of single phase nanocrystalline NdFeO$_{3}$ perovskite was confirmed by different characterization techniques: XRD, FTIR, TEM, BET, SEM, and EDAX. The nanoperovskite was successfully used as a sensor component with a carbon paste electrode (CpE) for the determination of ketotifen in pharmaceutical formulations. Ketotifen, an antiallergic drug, is utilized for the treatment of asthma attacks, rhinitis, skin allergies, and anaphylaxis. Sodium dodecyl sulfate (SDS) was employed in a surface assembly mode to improve the sensitivity of the sensor response. The proposed sensor, NdFeO$_{3}$ in situ modified …
Decolorization Of Reactive Orange 16 Via Ferrate(Vi) Oxidation Assisted By Sonication, Serkan Şahi̇nkaya
Decolorization Of Reactive Orange 16 Via Ferrate(Vi) Oxidation Assisted By Sonication, Serkan Şahi̇nkaya
Turkish Journal of Chemistry
The decolorization of azo dye C.I. reactive orange 16 (RO 16) via ferrate(VI) and sono-ferrate(VI) methods, which is the combination of the ferrate(VI) oxidation method with sonication, has been achieved in the present study. The influences of some important operating parameters, which are the initial pH, the concentration of potassium ferrate(VI) (K$_{2}$FeO$_{4})$ and the RO 16 dye, and ultrasonic density (for only the sono-ferrate(VI) method), on the color removal have been investigated. The optimum conditions have been determined as pH = 7 and [K$_{2}$FeO$_{4}$] = 50 mg L$^{-1}$ for the individual ferrate(VI) oxidation method and pH = 7 and [K$_{2}$FeO$_{4}$] …
Diastereoselective Synthesis Of Novel 2,5-Dioxopyrrolidine Derivatives Via Biocatalytic Domino Reactions, Saadieh Mohajer, Robabeh Baharfar
Diastereoselective Synthesis Of Novel 2,5-Dioxopyrrolidine Derivatives Via Biocatalytic Domino Reactions, Saadieh Mohajer, Robabeh Baharfar
Turkish Journal of Chemistry
A series of novel 2,5-dioxopyrrolidines were synthesized by the one-pot reaction of coumarin-3-carboxylic acids 1 with thiourea derivatives and alkyl isocyanides in the presence of Fe$_{3}$O$_{4}$ NPs @ lipase as heterogeneous reusable nanobiocatalysts with high yields.
Synchrotron X-Ray Diffraction Studies Of $\Beta $-Ca$_{2-X}M_{X}$Sio$_{4}$ ($M$ = Mg And Sr), Anti Prodjosantoso, Brendan Kennedy
Synchrotron X-Ray Diffraction Studies Of $\Beta $-Ca$_{2-X}M_{X}$Sio$_{4}$ ($M$ = Mg And Sr), Anti Prodjosantoso, Brendan Kennedy
Turkish Journal of Chemistry
The structures of Mg- and Sr-doped $\beta $-Ca$_{2}$SiO$_{4}$ have been established from high-resolution synchrotron X-ray powder diffraction. These silicates are all isostructural and the structures have been refined in the monoclinic space group, $P$2$_{1}$/$n$. As expected based on size arguments, the cell parameters increase as the amount of Sr increases and likewise decrease as the amount of Mg increases due the size effects of the dopant cation. In all cases the SiO$_{4}$ tetrahedra are essentially regular.
Ultrasonic Activation Of The Arylation Reaction Of Styrene Catalyzed By Transition Metals, Dhiab Atoui, Khemais Said, Ridha Ben Salem
Ultrasonic Activation Of The Arylation Reaction Of Styrene Catalyzed By Transition Metals, Dhiab Atoui, Khemais Said, Ridha Ben Salem
Turkish Journal of Chemistry
The arylation reaction of styrene was tested in the presence of different transition metal-based catalysts, mainly iron-based, given its low cost and its nonpolluting and nontoxic characteristics. The study of the effect of sonochemical activation on the evolution of the selectivity of the reaction is also proposed. Higher efficiency was observed for a very short period of time of just a few minutes. Furthermore, an improvement of the selectivity of the arylation of the external carbon of styrene was observed.
Online Coupling Electrochemical Preconcentration And Gfaas Technique As Effective Method For Determination Of Ultratrace Concentrations Of Antimony In Groundwater And Surface Water Samples, Lubomir Machynak, Martin Nemecek, Ernest Beinrohr, Frantisek Cacho
Online Coupling Electrochemical Preconcentration And Gfaas Technique As Effective Method For Determination Of Ultratrace Concentrations Of Antimony In Groundwater And Surface Water Samples, Lubomir Machynak, Martin Nemecek, Ernest Beinrohr, Frantisek Cacho
Turkish Journal of Chemistry
The present article describes a method of determination of low antimony concentrations using a graphite furnace AAS technique after electrochemical preconcentration. A 2-electrode flow-through cell was developed with a working electrode made of gold-coated porous carbon and an accessory Pt electrode. This cell worked in online coupling with the graphite furnace atomizer. Accumulation occurred from the 6 M hydrochloric acid solution and 2 M nitric acid was used to dissolve and transport antimony into the sampling loop. The sampling loop was placed on a 6-way valve. The preconcentrated solution was transported to the atomizer using an air jet. The detection …
Achieving Elusive Transformations With Organocatalysis: Direct $\Beta $-Carbon Activation Of Saturated Carbonyl Compounds, Rafik Rajjak Shaikh
Achieving Elusive Transformations With Organocatalysis: Direct $\Beta $-Carbon Activation Of Saturated Carbonyl Compounds, Rafik Rajjak Shaikh
Turkish Journal of Chemistry
Direct $\beta $-carbon activation of saturated carbonyl compounds for carrying out fast forward $\beta$-functionalization has been one of the most difficult to achieve tasks in catalysis. In the past few years, this challenging issue has attracted considerable attention among the chemical community that has led to fruitful developments to accomplish this elusive transformation. In this short review, we highlight recent developments for direct $\beta $-carbon functionalization of saturated carbonyl compounds based on conceptually new methods including oxidative enamine catalysis, $N$-heterocyclic carbene (NHC)-assisted catalysis, and photoredox catalysis.
Synthesis And Antinociceptive Activities Of Some Novel Benzimidazole-Piperidine Derivatives, Ümi̇de Demi̇r Özkay, Özgür Devri̇m Can, Nazli Turan, Betül Kaya Çavuşoğlu
Synthesis And Antinociceptive Activities Of Some Novel Benzimidazole-Piperidine Derivatives, Ümi̇de Demi̇r Özkay, Özgür Devri̇m Can, Nazli Turan, Betül Kaya Çavuşoğlu
Turkish Journal of Chemistry
In this study, a series of benzimidazole-piperidine derivatives were synthesized with the objective of developing potent antinociceptive agents. Some 2-(4-substituted-phenyl)-1-[2-(piperidin-1-yl)ethyl]-1$H$-benzimidazole derivatives were obtained by microwave-supported reaction of an appropriate 2-(4-substituted-phenyl)-1$H$-benzimidazole with 2-(piperidine-1-yl)ethyl chloride. The chemical structures of the compounds were elucidated by FT-IR, $^{1}$H NMR, $^{13}$C NMR, and HRMS spectral data. Antinociceptive activity was assessed by conducting hot-plate, paw-pressure, and formalin tests. Morphine (5 mg/kg, i.p) was used as a reference drug. Among the tested compounds 2a-2d and 2f-2h (10 mg/kg) increased the maximum possible effect (MPE) % values calculated for the hot-plate and paw-pressure tests and decreased the paw …
Synthesis And Mao Inhibitory Activity Of Novel Thiazole-Hydrazones, Özlem Atli, Yusuf Özkay
Synthesis And Mao Inhibitory Activity Of Novel Thiazole-Hydrazones, Özlem Atli, Yusuf Özkay
Turkish Journal of Chemistry
A series of new thiazole-hydrazones 3a-3n were synthesized, characterized, and screened for their $h$MAO-A and $h$MAO-B inhibitory activity by an in vitro fluorometric method. Selectivity indexes (SIs) were expressed as IC$_{50}$ (MAO-A) / IC$_{50}$ (MAO-B). Compound 3f showed promising $h$MAO-A inhibition with an IC$_{50}$ value of 1.20 $\mu $M and displayed a very significant SI of 0.04 towards $h$MAO-A. The mechanism of $h$MAO-A inhibition was investigated by enzyme kinetics using Lineweaver--Burk graphics. Compound 3f was further screened for its cytotoxicity by using a healthy NIH/3T3 mouse embryonic fibroblast cell line (ATCC CRL1658) and was evaluated as nontoxic at its effective …
A New Method For Simultaneous Determination Of Trace Amounts Of Cu(Ii) And Ni(Ii) Ions By Preconcentration And Spectrophotometric Analysis, Berri̇n Topuz, Şennur Merve Adanur, Arda Yalçuk
A New Method For Simultaneous Determination Of Trace Amounts Of Cu(Ii) And Ni(Ii) Ions By Preconcentration And Spectrophotometric Analysis, Berri̇n Topuz, Şennur Merve Adanur, Arda Yalçuk
Turkish Journal of Chemistry
Immediate preconcentration and spectrophotometric methods have been developed for the determination of trace amounts of cupric ion (Cu(II)) and nickel ion (Ni(II)) through a solid phase extraction with XAD-4-N,N'-bis-(salicylidene) cyclohexanediamine (XAD-4-SCHD) resin and a complex color reaction of the ions with 2,6-dimethyl-morpholine dithiocarbamate (DMMDTC) in Triton X-100 media. A high preconcentration factor of 125 was achieved. The spectrophotometric method was based on the measurements of the absorption of colored chelates of ions complexing with DMMDTC, and the adsorptions of the complex solutions were measured at their maximum absorption peaks at 460 and 328 nm for Cu(II) and Ni(II) ions, respectively. …
Synthesis Of Phosphorus-Containing Polyurethanes And Poly(Urethane-Acrylate)S, Mahi̇r Burak Südemen, Hacer Ayşen Önen
Synthesis Of Phosphorus-Containing Polyurethanes And Poly(Urethane-Acrylate)S, Mahi̇r Burak Südemen, Hacer Ayşen Önen
Turkish Journal of Chemistry
Solvent-based polyurethanes and poly(urethane-acrylate)s were synthesized using phosphorus-containing polyester polyols in order to compare the thermal properties of different polymer types. Since the location of the phosphorus group might have vital importance when comparing the thermal properties, phosphorus groups were kept on the pendant chains in poly(urethane-acrylate)s using phosphorus-containing urethane macromonomers while they were kept on the backbone in polyurethanes. The effect of molar mass of polyurethanes and pendant urethane chains of poly(urethane-acrylate)s on thermal properties was also investigated. Characterization of the synthesized polymers was carried out using FT-IR, GPC, NMR, and DSC followed by evaluation of the thermal properties.
Photoemissive Polymer Composite Based On New Y(Iii), Gd(Iii), And Tb(Iii) Complexes With N-Hydroxyphthalimide, Catalina Yarodara Rosca, Petronela Horlescu, Corneliu S.Stan, Daniel Sutiman
Photoemissive Polymer Composite Based On New Y(Iii), Gd(Iii), And Tb(Iii) Complexes With N-Hydroxyphthalimide, Catalina Yarodara Rosca, Petronela Horlescu, Corneliu S.Stan, Daniel Sutiman
Turkish Journal of Chemistry
In the present work, a green emitting composite with attractive photoluminescent properties was obtained through the embedding of the Tb$^{3+}$ complex with N-hydroxyphthalimide in a poly-(N-vinyl-pyrrolidone) matrix, which was further processed in thin or thick films. First, several complexes of Gd$^{3+}$, Tb$^{3+}$, and Y$^{3+}$ with N-hydroxyphthalimide with the general formula [M(NHF)$_{3}$(DMF)$_{2}$] were prepared at a 1:3 metal/ligand ratio. The Tb$^{3+}$ complex presents specific emission peaks, with the most intense peak located at 543 nm, thus being selected for incorporation in the poly(N-vinyl-pyrrolidone) matrix. The prepared complexes and composites were investigated through elemental analysis, thermal analysis, FT-IR, P-XRD, and SEM. The …
Experimental And Computational Studies On The Absorption Properties Of Novel Formazan Derivatives, Gülşen Türkoğlu, M. Emi̇n Çinar
Experimental And Computational Studies On The Absorption Properties Of Novel Formazan Derivatives, Gülşen Türkoğlu, M. Emi̇n Çinar
Turkish Journal of Chemistry
Eight novel 3-(4-(benzyloxy)phenyl)-5-(4-bromophenyl)-1-(4-substituted-phenyl)formazan (4a-4h) were synthesized by coupling of substituted phenylhydrazones with diazonium salts of 4-bromoaniline. The substituted phenylhydrazones, which are intermediate products, were obtained from the condensation of substituted phenylhydrazines with 4-(benzyloxy)benzaldehyde. All target compounds were characterized by using FTIR, $^{1}$H NMR, $^{13}$C NMR, LC$-$MS spectrometry, and elemental analysis. Absorption spectra of these compounds in solvents with different polarities were investigated thoroughly. Time-dependent density functional theory (TD-DFT) studies were conducted to shed light on their electronic structures, Kohn--Sham orbitals, and electronic transitions.
Synthesis, In Vitro Dna Interactions, Cytotoxicities, Antioxidative Activities, And Topoisomerase Inhibition Potentials Of Mn(Ii), Co(Ii), Ni(Ii), Cu(Ii), And Zn(Ii) Complexes With Azo-Oxime Ligands, Melek Çol Ayvaz, İbrahi̇m Turan, Bayram Dural, Seli̇m Demi̇r, Kaan Karaoğlu, Yüksel Ali̇yazicioğlu, Keri̇m Serbest
Synthesis, In Vitro Dna Interactions, Cytotoxicities, Antioxidative Activities, And Topoisomerase Inhibition Potentials Of Mn(Ii), Co(Ii), Ni(Ii), Cu(Ii), And Zn(Ii) Complexes With Azo-Oxime Ligands, Melek Çol Ayvaz, İbrahi̇m Turan, Bayram Dural, Seli̇m Demi̇r, Kaan Karaoğlu, Yüksel Ali̇yazicioğlu, Keri̇m Serbest
Turkish Journal of Chemistry
Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) transition metal complexes of 2-hydroxy-5-[(E)-(4-phenyl) diazenyl] benzaldehyde oxime and 2-hydroxy-5-[(E)-(4-nitrophenyl) diazenyl] benzaldehyde oxime ligands were synthesized and characterized through NMR, IR, ESI mass, and UV analysis. DNA binding abilities of the complexes were revealed using a UV-Vis spectrophotometer with the absorption titration and competitive binding techniques. Hydrolytic and oxidative DNA cleavage activities under different conditions were also proved. Topoisomerase I inhibition efficiencies and in vitro free radical scavenging activities of all complexes were examined. Finally, the selective cytotoxic potentials of all complexes were evaluated in human colon cancer, normal colon, and fibroblast cell lines …
Removal Of Pb(Ii) And Cd(Ii) From Aqueous Solution Using Alkaline-Modified Pumice Stone Powder (Psp): Equilibrium, Kinetic, And Thermodynamic Studies, Vivian Jonasi, Kaina Matina, Upenyu Guyo
Removal Of Pb(Ii) And Cd(Ii) From Aqueous Solution Using Alkaline-Modified Pumice Stone Powder (Psp): Equilibrium, Kinetic, And Thermodynamic Studies, Vivian Jonasi, Kaina Matina, Upenyu Guyo
Turkish Journal of Chemistry
Adsorption processes of Cd(II) and Pb(II) from aqueous solutions onto pumice stone powder (PSP) were investigated in batch mode. The influences of solution pH, contact time, adsorbent dosage, initial metal (M) concentration, and temperature on adsorption process were investigated. The kinetic and isotherm data were analysed using different model equations. The adsorption process was consistent with the Langmuir model for both metal ions with high R$^{2}$ and low $\chi^{2}$ values for both Pb(II) and Cd(II). The maximum monolayer adsorption capacities were 28.09 and 27.17 mg g$^{-1}$ for Pb(II) and for Cd(II), respectively. The pseudo-second order kinetic model explained the kinetic …
Adsorption Of Cu(Ii) On Three Adsorbents, Fe$_{3}$O$_{4}$/Ni/Ni$_{X}$B Nanocomposite, Carob (\Textit{Ceratonia Siliqua}), And Grape Seeds: A Comparative Study, Tüli̇n Deni̇z Çi̇ftçi̇
Adsorption Of Cu(Ii) On Three Adsorbents, Fe$_{3}$O$_{4}$/Ni/Ni$_{X}$B Nanocomposite, Carob (\Textit{Ceratonia Siliqua}), And Grape Seeds: A Comparative Study, Tüli̇n Deni̇z Çi̇ftçi̇
Turkish Journal of Chemistry
A novel adsorbent Fe$_{3}$O$_{4}$/Ni/Ni$_{x}$B nanocomposite was synthesized and used for the adsorption of copper. Moreover, natural adsorbents carob and grape seeds were used for this purpose. The surfaces and the elemental compositions of the adsorbents were characterized by SEM-EDX. The zero point charges of pH of Fe$_{3}$O$_{4}$/Ni/Ni$_{x}$B nanocomposite, carob, and grape seeds were found as 8.4, 6.0, and 5.6, respectively. The Langmuir, Freundlich, and Dubinin--Radushkevich isotherm models were used for the identification of the mechanism of the adsorption. The adsorptions of Cu(II) on the three adsorbents were well fitted to the Langmuir isotherm. The maximum adsorption capacities obtained from the …
Nanocomposite Copper Metal As An Efficient Heterogeneous Catalyst In Click Synthesis Of 1,2,3-Triazoles In Aqueous Media, Vajihe Nejadshafiee, Hossein Naeimi
Nanocomposite Copper Metal As An Efficient Heterogeneous Catalyst In Click Synthesis Of 1,2,3-Triazoles In Aqueous Media, Vajihe Nejadshafiee, Hossein Naeimi
Turkish Journal of Chemistry
Copper/periodic mesoporous organosilica (Cu/PMO) nanocomposites provided a highly active, reusable, globular, solid-phase catalyst for click chemistry. The reaction proceeds by mixing organohalides, sodium azide, alkyne, and the catalyst in an aqueous medium to afford the desired products. The cost efficiency and recyclability of the catalyst up to six runs without appreciable loss of activity and high yields of products make this procedure greener.
The Multiple Effects Of Organoclay And Solvent Evaporation On Hydrophobicity Of Composite Surfaces, Haci Hasan Yolcu, Ahmet Gürses, Rabah Boukherroub
The Multiple Effects Of Organoclay And Solvent Evaporation On Hydrophobicity Of Composite Surfaces, Haci Hasan Yolcu, Ahmet Gürses, Rabah Boukherroub
Turkish Journal of Chemistry
A superhydrophobic high-density polyethylene (HDPE)/organoclay composite material with a water-static contact angle of $\sim $162$^{\circ}$ and low hysteresis (7$^{\circ})$ was prepared by a simple solution-intercalation technique. This one-step method consists of the insertion of organoclay, produced through cation exchange with cetyltrimethylammonium bromide (CTAB), in the polymer matrix at 120 $^{\circ}$C in xylene. In this process, evaporation of the solvent and organoclay amount are key factors for the achievement of superhydrophobicity. We characterized composite material with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and contact angle measurements. The characterizations showed that the organoclay provides a place for …
Cyclic Voltammetry Behavior Of Tamoxifen In Different Electrolytes, Electrochemical Characterization, And Its Measurement By Differential Pulse Anodic Voltammetry, Zeinab Deris Falahieh, Mehdi Jalali, Mohammad Alimoradi
Cyclic Voltammetry Behavior Of Tamoxifen In Different Electrolytes, Electrochemical Characterization, And Its Measurement By Differential Pulse Anodic Voltammetry, Zeinab Deris Falahieh, Mehdi Jalali, Mohammad Alimoradi
Turkish Journal of Chemistry
Cyclic voltammetry (CV) was performed on tamoxifen (tam) using different electrodes and in various acidic electrolytes containing 10% v v$^{-1}$ methanol (MeOH). Tam oxidation was found to be most favorable using 0.1 mol L$^{-1}$ H$_{2}$SO$_{4}$. To investigate the mechanism, we performed chronoamperometry, CV at different scan rates, differential pulse anodic voltammetry (DPAV), and electrochemical impedance spectroscopy on tam-covered glassy carbon electrodes (GCEs). The electrode area, diffusion coefficient, and surface concentration ($\Gamma )$ of tam were calculated to be 0.062 cm$^{2}$, 3.65 $\times $ 10$^{-6}$ cm$^{2}$ s$^{-1}$, and 3.2 $\times $ 10$^{-10}$ mol cm$^{-2}$ respectively. Then the effects of different parameters …
Methanolysis Of Jatropha Curcas Oil Using K$_{2}$Co$_{3}$/Cao As A Solid Base Catalyst, Gajanan Sahu, Sujan Saha, Sudipta Datta, Prakash Chavan, Satyanarayan Naik
Methanolysis Of Jatropha Curcas Oil Using K$_{2}$Co$_{3}$/Cao As A Solid Base Catalyst, Gajanan Sahu, Sujan Saha, Sudipta Datta, Prakash Chavan, Satyanarayan Naik
Turkish Journal of Chemistry
Biodiesel, fatty acid methyl ester produced by the transesterification of vegetable oil with methanol, is a promising alternative to petroleum-based diesel fuel. In the present study, the methanolysis of high free fatty acid (FFA) $Jatropha$ $curcas$ oil in a transesterification reaction using K$_{2}$CO$_{3}$/CaO solid base catalyst was studied. The various reaction parameters in the transesterification reaction were also discussed. The catalyst was characterized by means of Fourier transform infrared, X-ray diffraction, temperature programmed desorption of CO$_{2}$, scanning electron microscopy, particle size analyzer, true density, and surface area analyzer. The optimum conversion of jatropha oil was 92% when the transesterification reaction …
Synthesis Of Novel 5-Substituted Phenyl-3-(P-Isopropylphenyl)-1-Phenylformazan And Their Biological Activities, Ayşe Şahi̇n Yağlioğlu, Hülya Şenöz
Synthesis Of Novel 5-Substituted Phenyl-3-(P-Isopropylphenyl)-1-Phenylformazan And Their Biological Activities, Ayşe Şahi̇n Yağlioğlu, Hülya Şenöz
Turkish Journal of Chemistry
Novel 1-substituted 3-(p-isopropylphenyl)-5-phenylformazans (3a--g) were synthesized and characterized by elemental analysis, $^{1}$H NMR, and FT-IR techniques and UV-visible spectroscopy. Antiproliferative activities of 3a--g against HeLa and C6 cells were determined using the BrdU cell proliferation ELISA assay. 5-Florouracil was used as the positive control. The effects of substituents (--H, --CH$_{3}$, and --I) and their positions ($ortho$, $meta$, and $para$) on the antiproliferative activities were evaluated. The results of the assay indicate that I substituent exhibited higher activity against the cells at the $meta$ and $para$ positions than --CH$_{3}$ and --H substituents. 3a--g exhibited both high antiproliferative activities against C6 cells …