Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

2019

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 25261 - 25290 of 26916

Full-Text Articles in Entire DC Network

Mwcnts-Fe$_{2}$O$_{3}$ Nanoparticle Nanohybrid-Based Highly Sensitive Electrochemical Sensor For The Detection Of Kaempferol In Broccoli Samples, Nomnotho Jiyane, Myalowenkosi I. Sabela, Suvardhan Kanchi, Phumlane S. Mdluli, Mavis Xhakaza, Olayide A. Arodola, Krishna Bisetty Jan 2019

Mwcnts-Fe$_{2}$O$_{3}$ Nanoparticle Nanohybrid-Based Highly Sensitive Electrochemical Sensor For The Detection Of Kaempferol In Broccoli Samples, Nomnotho Jiyane, Myalowenkosi I. Sabela, Suvardhan Kanchi, Phumlane S. Mdluli, Mavis Xhakaza, Olayide A. Arodola, Krishna Bisetty

Turkish Journal of Chemistry

This work reports an electrochemical sensor with a modified glassy carbon electrode for the detection of kaempferol. The method was tailored by the immobilization of multiwalled carbon nanotubes (MWCNTs) assimilated with Fe$_{2}$O$_{3}$ nanoparticles (NPs) onto the electrode surface to detect kaempferol using differential pulse voltammetry. Thermogravimetric, transmission electron microscopic, cyclic, and differential voltammetric techniques were employed to characterize the developed electrochemical sensor. The kaempferol produces an anodic quasireversible peak at pH 6.6 in phosphate buffer with Fe$_{2}$O$_{3}$NPs/MWCNTs/GCE. The current of the anodic peak at 0.32 V increases linearly upon addition of kaempferol standard, resulting in Ip($\mu $A) = 1.577($\mu $M) …

Go to article

Extraction Of High-Purity Silica From Rice Husk Via Hydrochloric Acid Leaching Treatment, Seitkhan Azat, Zhanar Sartova, Kalampyr Bekseitova, Kydyr Askaruly Jan 2019

Extraction Of High-Purity Silica From Rice Husk Via Hydrochloric Acid Leaching Treatment, Seitkhan Azat, Zhanar Sartova, Kalampyr Bekseitova, Kydyr Askaruly

Turkish Journal of Chemistry

The present paper aimed at the investigation of the effect of preliminary acid treatment on the structure and purity of extracted silica. In this study, the acid leaching of rice husk (RH) in 2 M hydrochloric acid solution before the calcination process at 600 $^{\circ}$C was proposed to achieve completely white silica with high specific surface area and low content of impurities. RH, selected from the Almaty Region, Kyzylorda Region, and Turkestan Region was used as the main silica source. The results confirmed that the highest purity (98.2%-99.7%) amorphous silica with a specific surface area between 120 and 980 m$^{2}$ …

Go to article

Magnetic Solid-Phase Extraction Based On Coriolus Versicolor-Immobilized $\Gamma $-Fe$_{2}$O$_{3}$ Nanoparticles For Preconcentration And Determination Of Al(Iii) In Water And Food Samples, Sadi̇n Özdemi̇r, Mustafa Serkan Yalçin, Ersi̇n Kilinç, Mustafa Soylak Jan 2019

Magnetic Solid-Phase Extraction Based On Coriolus Versicolor-Immobilized $\Gamma $-Fe$_{2}$O$_{3}$ Nanoparticles For Preconcentration And Determination Of Al(Iii) In Water And Food Samples, Sadi̇n Özdemi̇r, Mustafa Serkan Yalçin, Ersi̇n Kilinç, Mustafa Soylak

Turkish Journal of Chemistry

A method for preconcentration of Al(III) prior to its determination by inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed because the sensitivity of ICP-OES is insufficient for trace-level measurement of Al(III). The method is based on the use of Coriolus versicolor}-immobilized $\gamma $-Fe$_{2}$O$_{3}$ magnetic nanoparticles as a solid phase sorbent. The best experimental conditions were found as pH 6.0, 2.0 mL/min flow rate, 100 mg amount of C. versicoloron 150 mg of $\gamma $-Fe$_{2}$O$_{3}$ nanoparticles, and 500 mL of sample volume. The Al(III) absorbed on biosorbent was eluted with 5.0 mL of 1.0 mol/L HCl. Limit of detection, limit of …

Go to article

Design, Synthesis, Biological Evaluation And Molecular Docking Of Novel Molecules To Parp-1 Enzyme, Fati̇h Tok, Bedi̇a Kaymakçioğlu, Recep İlhan, Si̇nem Yilmaz, Petek Ballar Kirmizibayrak, Tuğba Taşkin Tok Jan 2019

Design, Synthesis, Biological Evaluation And Molecular Docking Of Novel Molecules To Parp-1 Enzyme, Fati̇h Tok, Bedi̇a Kaymakçioğlu, Recep İlhan, Si̇nem Yilmaz, Petek Ballar Kirmizibayrak, Tuğba Taşkin Tok

Turkish Journal of Chemistry

Poly (ADP-ribose) polymerase (PARP) enzyme catalyzes the transfer of ADP-ribose into target proteins. Therefore, PARP is responsible for DNA repair, cell proliferation, and cell death. In this study, potential PARP enzyme inhibitors were designed and synthesized. The synthesized compounds were elucidated by Fourier-transform infrared spectroscopy, $^{1}$H NMR, $^{13}$C NMR, heteronuclear single-quantum correlation, and mass spectrometry, and their purity was checked via thin-layer chromatography, high-performance liquid chromatography, and elemental analysis. A total of 63 newly synthesized compounds were screened in terms of PARP inhibition by cellular PARylation assay in the HeLa cell line. It was found that 19 compounds significantly inhibited …

Go to article

The Effect Of Starting Material Types On The Structure Of Graphene Oxide And Graphene, Fi̇li̇z Boran, Sevi̇l Çeti̇nkaya Gürer Jan 2019

The Effect Of Starting Material Types On The Structure Of Graphene Oxide And Graphene, Fi̇li̇z Boran, Sevi̇l Çeti̇nkaya Gürer

Turkish Journal of Chemistry

In this study, the effects of starting material types on graphene oxide (GO) are reported with the aim of developing graphene (GR) synthesis. The GOs were prepared from natural graphite (NG) powder and graphite nanoplate (GNp) based on the Hummers method. Two kinds of GR were successfully synthesized using GOs, which were prepared from NG and GNp in the presence of hydrazine and ammonia for 24 h at a 100 $^{\circ}$C reaction temperature. The synthesized GOs and GRs were characterized by X-ray diffraction (XRD) techniques, Fourier transform infrared, high-contrast transmission electron microscopy (HCTEM), dispersive Raman spectroscopic analyses, and elemental analyses. …

Go to article

Density Functional Theory-Supported Studies Of Structural And Electronic Properties Of Substituted-Phenol Derivatives Synthesized By Efficient O- Or C-Arylation Via Chan--Lam Or Suzuki Cross-Coupling Reactions, Hafiz Mansoor Ikram, Nasir Rasool, Muhammad Ali Hashmi, Muhammad Arfan Anjum, Kulsoom Ghulam Ali, Muhammad Zubair, Gulraiz Ahmad, Tariq Mahmood Jan 2019

Density Functional Theory-Supported Studies Of Structural And Electronic Properties Of Substituted-Phenol Derivatives Synthesized By Efficient O- Or C-Arylation Via Chan--Lam Or Suzuki Cross-Coupling Reactions, Hafiz Mansoor Ikram, Nasir Rasool, Muhammad Ali Hashmi, Muhammad Arfan Anjum, Kulsoom Ghulam Ali, Muhammad Zubair, Gulraiz Ahmad, Tariq Mahmood

Turkish Journal of Chemistry

The present study reports the efficient synthesis and computational studies of the structural and electronic properties of some interesting substituted phenol derivatives. Efficient and versatile procedures to synthesize a series of diaryl ether derivatives (2a-2c, 4a-4h) and bis-arylated products (5a-5c) are described. In this manuscript, using the commercially available starting material 1 and 3, a 1-step approach was developed by means of Cu(II)-mediated Chan-Lam and Pd-catalyzed Suzuki cross-coupling reactions to synthesize diaryl ether and bis-arylated products with moderate to good yields. The starting substrates, 2-bromo-4-methylphenol 1 or 2,4-dibromophenol 3, were both treated with several arylboronic acids, which led to the …

Go to article

In Silico And In Vitro Evaluation Of The Biological Activity Of Some Organic Sulfur-Containing Compounds, Victoria Osipova, Maria Polovinkina, Anastasia Osipova, Yulia Gracheva, Andrey Okhlobystin Jan 2019

In Silico And In Vitro Evaluation Of The Biological Activity Of Some Organic Sulfur-Containing Compounds, Victoria Osipova, Maria Polovinkina, Anastasia Osipova, Yulia Gracheva, Andrey Okhlobystin

Turkish Journal of Chemistry

It was predicted, using the Prediction of Activity Spectra for Substances online software, that organic sulfur-containing compounds 2,6-di-tert-butyl-4-mercaptophenol (1), 2,6-di-tert-butyl-4-(3-mercaptopropyl)phenol (2), bis-3-[3,5-di-tert-butyl-4-hydroxyphenyl)propyl] sulfide (3), bis(3,5-di-tert- butyl-4-hydroxyphenyl) disulfide (4), diphenyl disulfide (5), dibenzyl disulfide (6), dibutyl disulfide (7), di-tert-butyl disulfide (8), diallyl disulfide (9), and methyl propyl trisulfide (10) could possess antioxidant activity and act as active scavengers of oxygen metabolites. The antiradical activity of these species was analyzed and it was shown that they were able to react with electrochemically generated the superoxide anion radical. The rate constants for reactions of 1-10 with the superoxide anion radical were calculated. The …

Go to article

Acetylene-Bridged Triazine Π-Conjugated Structures: Synthesis And Liquid Crystalline Properties, Ni̇hat Akkurt, Mohammed Hadi Ali Al-Jumaili, Belkiz Bi̇lgi̇n Eran, Hale Ocak, Lokman Torun Jan 2019

Acetylene-Bridged Triazine Π-Conjugated Structures: Synthesis And Liquid Crystalline Properties, Ni̇hat Akkurt, Mohammed Hadi Ali Al-Jumaili, Belkiz Bi̇lgi̇n Eran, Hale Ocak, Lokman Torun

Turkish Journal of Chemistry

We report the synthesis and liquid crystalline properties of a new type of tribranched compound built up from triazine as the central core and electron-rich triazine rings as peripheral groups. An equimolar mixture of the star-shaped compound based on the 1,3,5-triazine core with 4-dodecyloxybenzoic acid produced an organic salt exhibiting a columnar mesophase with a dendritic growing texture at low temperatures. The liquid crystalline properties of the triazine-based compound and organic salt were investigated by differential scanning calorimetry and polarizing optical microscopy.

Go to article

The Promoted Synthesis Of Minoxidil By Magnetic Nanoparticles Of Cobalt Ferrite (Cofe$_{2}$O$_4$) As A Heterogeneous Reusable Catalyst, Ronak Eisavi, Fateme Ahmadi, Behzad Zeynizadeh, Mehri Kouhkan Jan 2019

The Promoted Synthesis Of Minoxidil By Magnetic Nanoparticles Of Cobalt Ferrite (Cofe$_{2}$O$_4$) As A Heterogeneous Reusable Catalyst, Ronak Eisavi, Fateme Ahmadi, Behzad Zeynizadeh, Mehri Kouhkan

Turkish Journal of Chemistry

Minoxidil (2,4-diamino-6-piperidinopyrimidine 3-oxide) was primarily recognized as a drug for reducing vascular resistance to blood flow. It was later introduced as a more important medicine for topical stimulation of hair growth and baldness reverting as well as treatment of androgenic alopecia through increasing prostaglandin endoperoxide synthesis. In this study, magnetic nanoparticles (MNPs) of spinel ferrites (MFe$_{2}$O$_{4}$, M = Co, Ni, Fe, Cu, and Zn) via solid-state grinding procedure were prepared and then characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer, and Fourier transform infrared techniques. The prepared nanoferrites were utilized as efficient and green heterogeneous …

Go to article

Synthesis And Characterization Of Novel Indanone-Based Spiro-Dihydrobenzofuran Derivatives, Meli̇ha Burcu Gürdere, Neşe Dürü, Yakup Budak, Mustafa Ceylan Jan 2019

Synthesis And Characterization Of Novel Indanone-Based Spiro-Dihydrobenzofuran Derivatives, Meli̇ha Burcu Gürdere, Neşe Dürü, Yakup Budak, Mustafa Ceylan

Turkish Journal of Chemistry

In this study, the synthesis and characterization of novel indanone-based spiro-dihydrobenzofuran derivatives were examined. Firstly, chalcone-like compounds 4a-k, ($E)$-2-benzylidene-2,3-dihydro-1$H$-inden-1-one derivatives, were synthesized by the base-catalyzed addition of benzaldehyde derivatives to 2,3-dihydro-1$H$-inden-1-one. Then Mn(OAc)$_{3}$-mediated addition of dimedone (2) to the chalcone-like compounds gave two novel spiro-dihydrobenzofuran isomers: (3$S)$-6,6-dimethyl-3-aryl-6,7-dihydro-3$H$-spiro [benzofuran-2,2'-indene]-1',4(3'$H$,5$H)$-dione (5a-k) and (2'$S)$-6,6-dimethyl-2-aryl-6,7-dihydro-2$H$-spiro[benzofuran-3,2'-indene]-1',4(3'$H$,5$H)$-dione (6a-k) in good yields. The isomers were separated by column chromatography and their structures were elucidated on the basis of spectral data (NMR, IR) and elemental analysis.

Go to article

Electrochemical Responses Of Flexible Graphite In H$_2$So$_4$, Mehmet Suha Yazici Jan 2019

Electrochemical Responses Of Flexible Graphite In H$_2$So$_4$, Mehmet Suha Yazici

Turkish Journal of Chemistry

Asymmetric capacitors are gaining attention due to their hybrid nature with higher power and energy density compared to individual batteries or capacitors. Electrochemical and structural characteristics of flexible graphite in 40% H$_{2}$SO$_{4\, }$electrolyte are investigated using electrochemical and microscopy techniques. There is a correlation between intercalation of electrolyte and the enlargement of interlayer spacing and electrochemical response. Conditions favoring planar orientation are electrochemically less active and more stable in such corrosive electrolytes. There are response variations between plain and resin-impregnated flexible graphite samples. The reaction peak seems to be reversible for resin impregnated samples while plain samples show continuous intercalation. …

Go to article

Natural Diterpenoid Alysine A Isolated From Teucrium Alyssifolium Exerts Antidiabetic Effect Via Enhanced Glucose Uptake And Suppressed Glucose Absorption, Alaatti̇n Şen, Buket Ayar, Anil Yilmaz, Özden Özgün Acar, Gurbet Çeli̇k Turgut, Gülaçti Topçu Jan 2019

Natural Diterpenoid Alysine A Isolated From Teucrium Alyssifolium Exerts Antidiabetic Effect Via Enhanced Glucose Uptake And Suppressed Glucose Absorption, Alaatti̇n Şen, Buket Ayar, Anil Yilmaz, Özden Özgün Acar, Gurbet Çeli̇k Turgut, Gülaçti Topçu

Turkish Journal of Chemistry

Teucrium species have been used in folk medicine as antidiabetic, antiinflammatory, antiulcer, and antibacterial agents. We have explored in vitro antidiabetic impacts of 2 natural diterpenoids, alysine A and alysine B, isolated from Teucrium alyssifolium. The lactate dehydrogenase (LDH) cytotoxicity assay, glucose uptake test, glucose utilization (glycogen content) test, glucose transport test, glucose absorption ($\alpha $-glucosidase activity) test, insulin secretion test, RNA isolation and cDNA synthesis assay, qPCR quantification assays, and statistical analyses were carried out in the present study. Alysine A exerted the following effects at non-cytotoxic doses: . Enhanced the glucose uptake, as much as the insulin in …

Go to article

Modeling And Optimizing Microwave-Assisted Extraction Of Antioxidant Compounds From Marigold Calendula Officinalis L. Using Response Surface Methodology, Burcu Bekdeşer Jan 2019

Modeling And Optimizing Microwave-Assisted Extraction Of Antioxidant Compounds From Marigold Calendula Officinalis L. Using Response Surface Methodology, Burcu Bekdeşer

Turkish Journal of Chemistry

Calendula officinalis L. is a commercially important plant that finds application in the treatment of various diseases in traditional medicine. The total antioxidant capacity, radical scavenging activity, and total phenolic content of marigold extracts were investigated by Folin, CUPRAC, and DPPH assays, respectively. The optimum operating conditions of microwave-assisted extraction (MAE) including temperature, extraction time, solvent-to-solid ratio, and solvent concentration were ascertained by employing response surface methodology (RSM). The solvent (ethanol) concentration was the most significant operating factor among all responses of MAE. At the optimum extraction conditions, the maximum yield of total phenolic content, total antioxidant capacity, and radical …

Go to article

Investigation Of The Effects Of Some Water-Soluble Vitamins On Glutathione Reductase Enzyme Purified From Bovine Liver, Mehmet Riza Kivanç, Vedat Türkoğlu Jan 2019

Investigation Of The Effects Of Some Water-Soluble Vitamins On Glutathione Reductase Enzyme Purified From Bovine Liver, Mehmet Riza Kivanç, Vedat Türkoğlu

Turkish Journal of Chemistry

Glutathione reductase (GR, EC 1.8.1.7) is an antioxidant enzyme and is involved in the reducing reaction of oxidized glutathione. Glutathione and reduced glutathione are very crucial for micro- and macroorganisms because of their barrier function against radicals. Therefore, the aim of this article was to purify GR and evaluate the relationship between purified GR and vitamins. GR was purified from bovine liver using 2',5'-ADP Sepharose 4B column materials. To check the purity of each subunit of the enzyme, SDS-PAGE electrophoresis was performed and each one was 55 kDa. Afterwards, specific activity and purified ratio for the enzyme were calculated as …

Go to article

One-Pot Synthesis Of Quinazolin-4(3$H$)-Ones And 2,3-Dihydroquinazolin-4(1$H$)-Ones Utilizing $N$-(2-Aminobenzoyl)Benzotriazoles, İlbi̇lge Merve Şenol, İlhami̇ Çeli̇k, İlker Avan Jan 2019

One-Pot Synthesis Of Quinazolin-4(3$H$)-Ones And 2,3-Dihydroquinazolin-4(1$H$)-Ones Utilizing $N$-(2-Aminobenzoyl)Benzotriazoles, İlbi̇lge Merve Şenol, İlhami̇ Çeli̇k, İlker Avan

Turkish Journal of Chemistry

A convenient and efficient method has emerged for the one-pot synthesis of substituted quinazolin-4(3$H)$-ones and nonaromatic alkaloids. 2-Substituted quinazolin-4(3H)-ones, 2,3-disubstituted quinazolin-4(3$H)$-ones, and 2,3-dihydroquinazolin-4(1$H)$-ones were obtained at yields of 46% to 95% by a one-pot reaction of $N$-(2-aminobenzoyl) benzotriazoles with amines and orthoesters or aldehydes under catalyst-free conditions.

Go to article

Evaluation Of The Enrichment And Amplification Effect Of Pentachlorobenzene With Lower Bioconcentration In The Food Chain Before And After Modification, Ruihao Sun, Meijin Du, Yu Li Jan 2019

Evaluation Of The Enrichment And Amplification Effect Of Pentachlorobenzene With Lower Bioconcentration In The Food Chain Before And After Modification, Ruihao Sun, Meijin Du, Yu Li

Turkish Journal of Chemistry

In this paper, in order to construct a 3D quantitative structure--activity relationship (QSAR) model with the chlorobenzene (CB) molecular structure parameter as an independent variable and the octanol-water partition coefficient ($K_{OW})$ as a dependent variable, 9 kinds of CB molecules were used as training sets and 3 kinds of CB molecules were used as test sets. We adopted the QSAR module in the Sybyl-X2.0 software from the Tripos Corporation (USA). The molecular modification of the pentachlorobenzene molecule with low bioconcentration was carried out by combining a three-dimensional contour map and fractional factorial design. The results showed that the toxicity, migration, …

Go to article

The Solvatochromism And Electronic Structure Of (E)-2-(2-Hydroxystyryl)Quinolin-8-Ol, Ayşegül Gümüş, Yadi̇gar Gülseven Sidir, İsa Sidir, Selçuk Gümüş Jan 2019

The Solvatochromism And Electronic Structure Of (E)-2-(2-Hydroxystyryl)Quinolin-8-Ol, Ayşegül Gümüş, Yadi̇gar Gülseven Sidir, İsa Sidir, Selçuk Gümüş

Turkish Journal of Chemistry

The (E)-2-(2-hydroxystyryl)quinolin-8-ol (abbreviated as HSQ) molecule was synthesized and characterized. The ESIPT, solvatochromism properties, electronic structure, and ground and excited electric dipole moments of this molecule were measured using absorption and fluorescence spectra recorded in 13 different solvents. Its electronic structure via electronic transitions was investigated to find the quantitative values of solvatochromism properties by LSER calculations. The ESIPT mechanism was clarified; ground and excited dipole moments were determined using solvatochromic shift methods. The DFT (B3LYP)/6-311$++$G(d,p) method and basis set with potential energy surface (PES) calculations of proton transfer were used to explain the ESIPT mechanism. NBO analysis, NLO properties, …

Go to article

Design, Synthesis, And Antitumor Evaluation Of Novel Methylene Moiety-Tethered Tetrahydroquinoline Derivatives, Esaam Hamied Ahmed Hanashalshahaby, Canan Ünaleroğlu, Ayşe Ak Can, Alp Özgün, Bora Gari̇pcan Jan 2019

Design, Synthesis, And Antitumor Evaluation Of Novel Methylene Moiety-Tethered Tetrahydroquinoline Derivatives, Esaam Hamied Ahmed Hanashalshahaby, Canan Ünaleroğlu, Ayşe Ak Can, Alp Özgün, Bora Gari̇pcan

Turkish Journal of Chemistry

Novel methylene-tethered tetrahydroquinolines (THQs) and cyclopenta[$b$]pyridines were synthesized by one-pot multicomponent reactions of Mannich bases, enolizable ketones, and NH$_{4}$OAc in water by an environmentally friendly K-10 montmorillonite clay-catalyzed reaction. The cytotoxic activities of 1-(2-methyl-8-methylene-5,6,7,8-tetrahydroquinolin-3-yl)ethanone (9a), ethyl 2-methyl-8-methylene-5,6,7,8-tetrahydroquinoline-3 carboxylate (9b), and 1-(2-methyl-7-methylene-6,7-dihydro-5$H$-cyclopenta[$b$]pyridin-3-yl)ethanone (11a) were tested against rat glioblastoma (C6), human breast cancer (MCF-7), prostate cancer (PC3), neuroblastoma (SH-SY5Y), and mouse fibroblast (L929) cell lines in a concentration-dependent (50-300 μM) and time-dependent (24-72 h) manner and expressed as IC$_{50\, }$values. The results showed that compound 9a induced the lowest IC$_{50\, }$values in all cell lines ranging from 111 ± 1.1 μM to …

Go to article

Synthesis And Catalytic Activity Of Ionic Palladium \Textit{N}-Heterocyclic Carbene Complexes, Sedat Yaşar, Mi̇tat Akkoç, Namik Özdemi̇r, İsmai̇l Özdemi̇r Jan 2019

Synthesis And Catalytic Activity Of Ionic Palladium \Textit{N}-Heterocyclic Carbene Complexes, Sedat Yaşar, Mi̇tat Akkoç, Namik Özdemi̇r, İsmai̇l Özdemi̇r

Turkish Journal of Chemistry

The synthesis of 3 benzimidazole-based ionic Pd(II)-NHC complexes (NHC:$N$-heterocyclic carbene) is presented. The structures of the complexes are as follows: [NHC-PdBr$_{3}$]$^{-}$[NHC]$^{+}$. The ionic palladium(II)-NHC complexes were synthesized in high yields and were fully characterized by nuclear magnetic resonance spectroscopy, X-ray diffraction, LC-MS/MS, and elemental analysis. These complexes have been identified as active catalysts in Suzuki-Miyaura reactions in a solution of 2-propanol and water at room temperature for different aryl bromides.

Go to article

Step-By-Step Optimization Of The Hilic Method For Simultaneous Determination Of Abacavir, Lamivudine, And Zidovudine From Dosage Form, Cem Erkmen, Mehmet Gümüştaş, Si̇bel Ayşil Özkan, Bengi̇ Uslu Jan 2019

Step-By-Step Optimization Of The Hilic Method For Simultaneous Determination Of Abacavir, Lamivudine, And Zidovudine From Dosage Form, Cem Erkmen, Mehmet Gümüştaş, Si̇bel Ayşil Özkan, Bengi̇ Uslu

Turkish Journal of Chemistry

Combined therapy for HIV treatment shows superior efficacy in comparison to single therapy. Furthermore, the separation and determination of the combined dosage forms hold a significant place in the pharmaceutical industry. Not only reverse phase high-performance liquid chromatography (HPLC) but also hydrophilic interaction liquid chromatography (HILIC) can be used for these purposes. Contrary to conventional RP systems, HILIC may be an alternative for the analysis of polar substances. The aim of this study was the step-by-step development of a simple, rapid, and reliable method for the simultaneous determination of antiviral compounds from their marketed formulation (Trizivir). In order to achieve …

Go to article

Synthesis, Characterization, And Investigation Of Singlet Oxygen, Dna Interaction, And Topoisomerase I Inhibition Properties Of Novel Zinc(Ii) Phthalocyanine, Ümi̇t Demi̇rbaş Jan 2019

Synthesis, Characterization, And Investigation Of Singlet Oxygen, Dna Interaction, And Topoisomerase I Inhibition Properties Of Novel Zinc(Ii) Phthalocyanine, Ümi̇t Demi̇rbaş

Turkish Journal of Chemistry

In this work, phthalonitrile (3) and zinc(II) phthalocyanine (4) were prepared. To determine the photodynamic therapy potential of compound 4, singlet oxygen quantum yield, DNA binding and cleavage, and topoisomerase I inhibition experiments were performed. The singlet oxygen quantum yield value of compound 4 was found higher than that of the standard unsubstituted zinc(II) phthalocyanine compound (Std-ZnPc). The binding experiments showed that compound 4 interacted with ct-DNA strongly via nonintercalation mode. pBR322 plasmid DNA cleavage activity of the compound was investigated using agarose gel electrophoresis. The results showed that the compound 4 had important DNA cleavage activity. The E. coli …

Go to article

Aqueous Two-Phase Extraction Technique Based On Magnetic Ionic Liquid-Nonionic Surfactant For Phenolic Acids In Grape, Apple, Pear, And Banana, Taşkin Mumcu, Serap Seyhan Bozkurt Jan 2019

Aqueous Two-Phase Extraction Technique Based On Magnetic Ionic Liquid-Nonionic Surfactant For Phenolic Acids In Grape, Apple, Pear, And Banana, Taşkin Mumcu, Serap Seyhan Bozkurt

Turkish Journal of Chemistry

An aqueous two-phase extraction system was constituted using magnetic ionic liquid-nonionic surfactant for phenolic acids and the developed method was applied to apple, grape, pear, and banana samples. Ionic liquids based on imidazolium containing butyl, allyl, and benzyl groups were used for extraction. The parameters influencing the extraction efficiency such as volume of ionic liquids, type and amount of surfactant and salt, ultrasound extraction time, temperature, and sample pH were optimized. The extraction efficiencies of ionic liquids were compared for phenolic acids under optimized conditions. Limits of detection and limits of quantification were in the range of 1.34-1.56 μg L$^{-1\, …

Go to article

Synthesis Of Hofmann-Type Zn(H$_2$O)$_2$Ni(Cn)$_4$.Ng (G = Water And 1,4-Dioxane) Clathrates And The Determination Of Their Structural Properties By Various Spectroscopic Methods, Zeki̇ Kartal, Onur Şahi̇n, Abdülkeri̇m Yavuz Jan 2019

Synthesis Of Hofmann-Type Zn(H$_2$O)$_2$Ni(Cn)$_4$.Ng (G = Water And 1,4-Dioxane) Clathrates And The Determination Of Their Structural Properties By Various Spectroscopic Methods, Zeki̇ Kartal, Onur Şahi̇n, Abdülkeri̇m Yavuz

Turkish Journal of Chemistry

Two new 2-dimensional cyanide-bridged coordination polymers [Zn(H$_{2}$O)$_{2}$Ni(CN)$_{4}$ 6(H$_{2}$O) and Zn(H$_{2}$O)$_{2}$ Ni(CN)$_{4}$ 3(C$_{4}$H$_{8}$O$_{2})$], which were similar to Hofmann-type clathrates, were synthesized based on [Ni(CN)$_{4}$]$^{2-}$ and Zn$^{2+}$ as building blocks. These substances were synthesized as compounds in crystalline form. Thes tructures of the crystalline compounds were characterized via their spectral analyses. General information about the structures of the newly obtained Hofmann-type clathrates was obtained from their vibration spectra by considering significant changes in the vibration peaks of the cyanide group, water ligand molecule, and guest molecules (water and 1,4-dioxane). The thermal behavior of the Hofmann-type clathrates was investigated in the range of …

Go to article

Dispersive Liquid-Liquid Microextraction Of Parabens From Pharmaceuticals And Personal Care Products Prior To Their Determination Using Hplc-Dad, Malek Hassan, Usama Alshana, Nusret Ertaş Jan 2019

Dispersive Liquid-Liquid Microextraction Of Parabens From Pharmaceuticals And Personal Care Products Prior To Their Determination Using Hplc-Dad, Malek Hassan, Usama Alshana, Nusret Ertaş

Turkish Journal of Chemistry

Dispersive liquid--liquid microextraction followed by a back-extraction step was combined with HPLC-DAD for the determination of four parabens (i.e. methyl-, ethyl-, propyl-, and butylparaben). Optimum extraction conditions were found as follows: 225 $\mu $L of chloroform, 0.75 mL of ethanol, 7.5 mL of aqueous solution and within an extraction time of 15 s. Back-extraction into 100 $\mu $L of 50 mM sodium hydroxide solution within 20 s resulted in a reversed-phase HPLC-compatible extract. The analytes were separated at 20 $^{\circ}$C using methanol (A) and water (B), 40:60 (A:B, v/v) as the mobile phase, a flow rate of 1.0 mL min$^{-1}$ …

Go to article

Surface Modification Of Polyvinyl Chloride By Polyacrylic Acid Graftas A Polyelectrolyte Membrane Using Ar Plasma, Alaa Fahmy, Mouhamed Abu-Saied, Nasser Morgan, Walid Qutop, Hassan Abdelbary, Tarek Salama Jan 2019

Surface Modification Of Polyvinyl Chloride By Polyacrylic Acid Graftas A Polyelectrolyte Membrane Using Ar Plasma, Alaa Fahmy, Mouhamed Abu-Saied, Nasser Morgan, Walid Qutop, Hassan Abdelbary, Tarek Salama

Turkish Journal of Chemistry

This work reports the synthesis and properties of a new membrane based on polyvinyl chloride (PVC) grafting with polyacrylic acid (PAA) using argon (Ar) plasma. The membranes of PVC were synthesized by solution-casting method, where PAA was deposited as an ultrathin film onto PVC using dielectric barrier discharge at atmospheric pressure with Ar gas. The surface characteristics and chemical composition of the modified membranes were analyzed by water contact angle, scanning electron microscopy, and Fourier transform infrared spectroscopy. Moreover, the electrochemical properties of the membrane were investigated via ion exchange capacity for the purpose of using it as a polyelectrolyte …

Go to article

An Ultrasensitive Electrochemical Immunosensor Platform Based On Disposable Ito Electrode Modified By 3-Cptms For Early Detection Of Parathyroid Hormone, İnci̇ Uludağ, Mustafa Kemal Sezgi̇ntürk Jan 2019

An Ultrasensitive Electrochemical Immunosensor Platform Based On Disposable Ito Electrode Modified By 3-Cptms For Early Detection Of Parathyroid Hormone, İnci̇ Uludağ, Mustafa Kemal Sezgi̇ntürk

Turkish Journal of Chemistry

Parathyroid hormone (PTH) is a polypeptide containing 84 amino acids secreted by cells of the parathyroid glands. Imbalances of parathyroid levels cause medical problems such as osteoporosis, mental disorders, pancreatitis, kidney stones, cancer, and other symptoms. In this study, we aimed to design an ultrasensitive electrochemical immunosensor for PTH detection. Indium tin oxide (ITO) was used as an electrode for electrochemical impedance spectroscopy (EIS) measurements. ITO sheets were modified by using 3-cyanopropyltrimethoxysilane (3-CPTMS) self-assembled monolayers (SAMs) for immobilizing the anti-PTH antibody via covalent interactions. Cyclic voltammetry (CV) and EIS methods were applied to characterize immobilization steps. Therefore, 1% was selected …

Go to article

Synthesis And Characterization Of Unsaturated Diacyl And Alkyl-Acyl Piperazine Derivatives, Sai̇t Sari, Seda Ünalan, Mehmet Yilmaz Jan 2019

Synthesis And Characterization Of Unsaturated Diacyl And Alkyl-Acyl Piperazine Derivatives, Sai̇t Sari, Seda Ünalan, Mehmet Yilmaz

Turkish Journal of Chemistry

The aim of this study is to obtain new unsaturated piperazine compounds by the reactions of piperazine (1a) and piperazine derivatives (1b-1d) with acylation reactive groups (a-2j). Methacryloyl piperazine (1b) was synthesized from the reaction of methacrylic anhydride with piperazine (1a). Acyl chlorides (2b-2d) were prepared from the reaction of thionyl chloride with carboxylic acids (3a-3c) obtained as a result of the reaction with malonic acid and suitable aldehyde (5-methylfuran-2-carbaldehyde for 3a, cinnamaldehyde for 3b, and thiophene-2-carbaldehyde for 3c), respectively, by literature methods. Acyl chlorides 2ed and 2f }were obtained from the reaction of commercially purchased carboxylic acids 3d and …

Go to article

The Role Of Diazacrown Ether In The Enhancement Of The Biological Activity Of Silver Nanoparticles, Sarvinaz Hajiyeva, Ulviyya Hasanova, Zarema Gakhramanova, Aygun Israyilova, Khudaverdi Ganbarov, Eldar Gasimov, Fuad Rzayev, Goncha Eyvazova, Alakbar Huseynzada, Gunel Aliyeva, Ilaha Hasanova, Abel Maharramov Jan 2019

The Role Of Diazacrown Ether In The Enhancement Of The Biological Activity Of Silver Nanoparticles, Sarvinaz Hajiyeva, Ulviyya Hasanova, Zarema Gakhramanova, Aygun Israyilova, Khudaverdi Ganbarov, Eldar Gasimov, Fuad Rzayev, Goncha Eyvazova, Alakbar Huseynzada, Gunel Aliyeva, Ilaha Hasanova, Abel Maharramov

Turkish Journal of Chemistry

The nanostructuring of hydroxyl-substituted diazacrown-ether (DC) by silver nanoparticles was obtained by green synthesis method in order to increase the antibacterial activity of silver nanoparticles. The synthesized DC, nanoparticles, and nanosupramolecular complex (Ag@DC) were studied by TEM, powder-XRD, and NMR, IR, and UV spectroscopy methods. The Ag@DC nanostructures were uniform and their sizes ranged from 8 to 18 nm. IR and UV spectra revealed the noncovalent formation of the nanosupramolecular complex. The antibacterial activities of the prepared active agents were investigated on gram-positive and gram-negative bacteria by twofold microdilution method. Ultrastructural study by TEM was performed on \textit{E. coli} BDU12 …

Go to article

Conformational Communication Mediates The Reset Step In T6a Biosynthesis, Amit Luthra, Naduni Paranagama, William Swinehart, Susan Bayooz, Phuc Phan, Vanessa Quach, Jamie M. Schiffer, Boguslaw Stec, Dirk Iwata-Reuyl, Manal A. Swairjo Jan 2019

Conformational Communication Mediates The Reset Step In T6a Biosynthesis, Amit Luthra, Naduni Paranagama, William Swinehart, Susan Bayooz, Phuc Phan, Vanessa Quach, Jamie M. Schiffer, Boguslaw Stec, Dirk Iwata-Reuyl, Manal A. Swairjo

Chemistry Faculty Publications and Presentations

The universally conserved N 6-threonylcarbamoylade nosine (t 6 A) modification of tRNA is essential for translational fidelity. In bacteria, t 6 A biosynthesis starts with the TsaC/TsaC2-catalyzed synthesis of the intermediate threonylcarbamoyl adenylate (TC-AMP), followed by transfer of the threonylcarbamoyl (TC) moiety to adenine-37 of tRNA by the TC-transfer complex comprised of TsaB, TsaD and TsaE sub-units and possessing an ATPase activity required for multi-turnover of the t 6 A cycle. We report a 2.5-˚ A crystal structure of the T. maritima TC-transfer complex (TmTsaB 2 D 2 E 2) bound to Mg 2+-ATP in the AT-Pase site, and substrate …

Go to article

Dodd-Frank Act And Its Impact On The Municipal Issuers, Underwriters, And Advisors, Todd Meierhenry Jan 2019

Dodd-Frank Act And Its Impact On The Municipal Issuers, Underwriters, And Advisors, Todd Meierhenry

South Dakota Law Review

No abstract provided.

Go to article

First Prev Next Last