Matematik ve Fen Bilimleri Eğitimi Bölümü Koleksiyonu

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Gamma irradiation effects on diphenhydramine hydrochloride: an EPR study
(Taylor and Francis Ltd., 2024) Sütçü, Kerem; Aydın, Murat
This study seeks to detect and characterize the free radicals generated in gamma-irradiated diphenhydramine hydrochloride (DP-HCl), a precursor for an antihistamine drug. The investigation aims to assess the radiation sensitivity of DP-HCl under varying microwave power, radiation doses, temperature conditions, and storage durations. After irradiation with 14 kGy, the observed radical associated with the –ĊHCH2N– fragment exhibited a singlet signal with a g-value of g = 2.0016 ± 0.0005. The signal intensities from experimental spectra within the 2–20 kGy dose range were found to exhibit the optimal fit with a polynomial function. Experimental spectra were recorded in the temperature range of 123–423 K to investigate whether distinct types of radicals were formed at low and high temperatures. Furthermore, the stability of the free radicals generated in the irradiated sample was assessed by determining the extinction curves of the signal intensities of the sample. The novelty of this study lies in examining the radiation sensitivity of the –ĊHCH2N– radical, demonstrating its remarkable stability across different temperatures and storage durations. This leads to the conclusion that radiation sterilization of the DP-HCl sample is not suitable.
Phosphorus-nitrogen compounds: Part 76. design and syntheses of dispiro- and trispiro(N/N)cyclotriphosphazenes: Conformational and structural analyses, chirality, electrochemical, dye-sensitized solar cells, and bioactivity studies
(American Chemical Society, 2024) Cemaloğlu, Reşit; Asmafiliz, Nuran; Tümer, Yasemin; Hökelek, Tuncer; Kılıç, Zeynel; Çelik, Nejla Nur; Açık, Leyla; Güzel, Remziye; Erdal, Gülbahar Güzel
The reactions of monospirocyclotriphosphazenes (1 and 2) with N-methyl-1,3-diaminopropane gave unsymmetrical cis-(3 and 5) and trans-(4 and 6) dispirocyclotriphosphazenes. Trans-cis-trans (tct) (7 and 11), cis-cis-cis (ccc) (8 and 12), trans-trans-cis (ttc) (9 and 13), and cis-trans-trans (ctt) (14) trispirocyclotriphosphazenes were obtained from the reactions of 3 and 5 and 4 and 6 with N-methyl-1,3-diaminopropane. cis-Dispirocyclotriphosphazenes (3 and 5) exist as “pseudomesoracemates”, while trans-dispirocyclotriphosphazenes (4 and 6) are in “racemates”. The existences of cis-3 and trans-4 as “pseudomesoracemate” and “racemate” were confirmed by 31P NMR spectra recorded by the addition of “chiral solvating agent (CSA)”. X-ray crystallography proved that the absolute configurations of each enantiomer of cis-5 and trans-6 are SS′ and RS′. Trispirocyclotriphosphazenes tct, ttc, ccc, and ctt exist as racemates, pseudomesoracemate, and meso forms. Furthermore, Hirshfeld surface analysis of the crystal structures of cis-5 and trans-6 revealed that the most significant contribution to crystal packing comes from H···H (58.2 and 57.6%, respectively). An oxidation-reduction wave was detected in the reversible cyclic voltammograms of the phosphazenes. The highest power conversion efficiency in dye-sensitized solar cell studies was obtained with cis-5. Additionally, trans-6 exhibited the lowest minimal inhibitory concentration value (78.1 μM) against Candida tropicalis, and it was observed to cleave pBR322 plasmid DNA.
Comparative study on silver nanoparticle synthesis using male and female pistacia khinjuk leaf extracts: Enhanced efficacy of female leaf extracts
(John Wiley and Sons Inc, 2024) Tural, Bilsen; Ertaş, Erdal; Batıbay, Hayri; Tural, Servet
This study aims to uncover the potential differences in bioactive compounds present in leaf extracts obtained from female and male individuals of Pistacia khinjuk, abundantly found in the Southeast Anatolia region of Turkey, and their roles in influencing the properties of synthesized silver nanoparticles (AgNPs). Results obtained through TEM and SEM imaging techniques determined the morphology and size of AgNPs synthesized from female (FL-AgNPs) and male (ML-AgNPs) leaf extracts. Additionally, FTIR spectrum analysis demonstrated the chemical composition of the FL-AgNPs, ML-AgNPs, and the extracts. Zeta potential and zeta sizer analyses revealed differences between nanoparticles obtained from female and male plants. The total phenolic content of leaf extracts from female plants is significantly higher than that obtained from male plants (female plants: 30.68±0.26 mg GAE/g, male plants: 24.22±0.37 mg GAE/g). Furthermore, FL-AgNPs (43.2±2.64 mg GAE/g) exhibit higher antioxidant activity compared to ML-AgNPs (31.7±1.16 mg GAE/g). ICP-MS analyses indicate that FL-AgNPs are synthesized with higher efficiency compared to ML-AgNPs (FL-AgNPs: 99.90±0.106 %, ML-AgNPs: 94.99±0.079 %). Finally, the antibacterial efficacy of FL-AgNPs and ML-AgNPs nanoparticles was evaluated agar well diffusion method against the pathogen Escherichia coli (E.Coli) and Staphylococcus aureus (S. Aureus].
General decay and blow up of solutions for a plate viscoelastic p(x)-Kirchhoff type equation with variable exponent nonlinearities and boundary feedback
(Taylor and Francis Ltd., 2024) Ferreira, Jorge; Pişkin, Erhan; Shahrouzi, Mohammad
In this paper, we consider a plate viscoelastic p(x)–Kirchhoff type equation with variable-exponent nonlinearities of the form (Figure presented.) associated with initial and boundary feedback. Under appropriate conditions on p(·), m(·) and q(·), general decay result along the solution energy is proved. By introducing a suitable auxiliary function, it is also shown that regarding negative initial energy and a suitable range of variable exponents, solutions blow up in a finite time.
Synthesis, molecular modeling, DFT studies, and EPR analysis of 1,4-dihydropyridines as potential calcium channel blockers
(Elsevier B.V., 2024) Aslan, Ebru Koçak; Lam, Kevin; Dengiz, Çağatay; Denzinger K.; Erdamar, Işık Yeşim Dicle; Huang, Sun; Wolber, Gerhard
1,4-Dihydropyridines (DHPs) are widely recognized as a highly effective class of L-type calcium channel blockers that offer significant therapeutic potential in managing cardiovascular conditions. Furthermore, their ability to target other types of calcium channels makes DHPs attractive candidates for therapeutic applications in neurological and psychiatric disorders. Close examination of the chemical structures of approved DHP-based antihypertensive drugs with a history of over forty years in the market reveals that the C-4 position is the least altered part of this privileged ring system. In the present study, we focused on this position and synthesized two novel compounds (DB1 and DB2) by carrying out chemical modifications on suitable positions of the main scaffold of DA1 (isobutyl 4-(benzo[d][1,3]dioxol-5-yl)-2,6,6-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate) that was previously identified as a DHP-based effective and selective inhibitor of T-type (Cav3.2) over L-type (Cav1.2) calcium channel. Based on whole-cell patch-clamp analysis on Cav1.2 and Cav3.2, DB1 with bromine group on the benzodioxole ring appeared to be a more effective and selective inhibitor of Cav3.2 compared to DB2 with nitro at the same locus. Molecular docking and molecular dynamics (MD) simulations were performed to investigate the binding mode of both DB1 isomers to Cav3.2. Furthermore, density functional theory (DFT) methods were employed to obtain information regarding the stability of the molecules by computing various parameters, such as electric dipole moment, band gap, electronegativity, and global chemical hardness-softness, related to their charge-transfer characteristics. According to DFT studies, DB1 also appeared to be chemically more stable than DB2. Finally, ionizing radiation-induced free radicals of gamma-irradiated DB1 and DB2 in powder form were examined utilizing the electron paramagnetic resonance (EPR) technique and the obtained data demonstrated that radiation sterilization is suitable for the dosage forms including DB1 and DB2. © 2024 Elsevier B.V.
The relationship between sea surface temperature and chlorophyll concentration of phytoplanktons in the Black Sea using remote sensing techniques
(Triveni Enterprises, 2012) Kavak, Mehmet Tahir; Karadoğan, Sabri
Present work investigated the relationship between Chlorophyll (Chl), of phytoplankton biomass, and sea surface temperature (SST) of the Black Sea, using Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Advanced Very High Resolution Radiometer (AVHRR) satellite imagery. Satellite derived data could provide information on the amount of sea life present (Brown algae, called kelp, proliferate, supporting new species of sea life, including otters, fish, and various invertebrates) in a given area throughout the world. SST from AVHRR from 1993 to 2008 showed seasonal, annual and interannual variability of temperature, monthly variability Chi from SeaWiFS from 1997 to 2009 has also been investigated. Chi showed two high peaks for the year 1999 and 2008. The correlation between SST and Chl for the same time has been found to be 60%. Correlation was significant at p<0.05. The information could also be useful in connection with studies of global changes in temperature and what effect they could have on the total abundance of marine life.
Age-related changes in the expression of ICAM-1 in the aorta of wistar albino rats
(Soc Chilena Anatomia, 2016) Ketani, Sennur; Karakoç, Zelal; Ketani, M. Aydın; Kılınç, Mehmet
ICAM-1 which is expressed by endothelial cells and leukocytes are observed as first markers in diseases such as transplant rejection, diabetes and atherosclerosis and in infections caused by various pathogens. In the present study, it is aimed to reveal the age-related changes in the expression of ICAM-1 on rats. Therefore, a total of 30 albino rats were taken at the age of 6, 18 and 24 months without gender discrimination. Rats were fed with standard pellet feed during the study. Afterwards, rats were sacrificed and tissue samples were collected from their rats, and the samples were evaluated under the light microscope by staining with immnunohistochemical method. It was determined that the expression of both aortic endothelial cells and endothelial cells in the media layer had been significantly increased based on the age.
On the decay and blow up of solutions for a quasilinear hyperbolic equations with nonlinear damping and source terms
(Springeropen, 2015) Pişkin, Erhan
In this work we investigate the global existence, decay, and blow up of solutions for a quasilinear hyperbolic equation. We prove the decay estimates of the energy function by using Nakao's inequality. Also, we obtain the blow up of solutions and lifespan estimates in three different ranges of the initial energy.
Radiation induced defects in timolol: temperature dependent electron paramagnetic resonance spectroscopy analysis
(Taylor & Francis Ltd, 2020) Erdamar, Işık Yeşim Dicle
Ionizing radiation-induced antihypertensive drug timolol in powder form was studied by means of electron paramagnetic resonance (EPR) technique as a function of temperature. The effect of temperature on EPR linewidth, intensity and spectra was investigated. The room temperature EPR spectra of ionizing radiation-induced timolol were recorded in dimethyl sulfoxide solution at a frozen state. The first-order kinetic mechanism rate constant of timolol was calculated. The findings on all EPR experimental data indicated that ionizing radiation-induced stable-free radical species on timolol are characterized byg= 2.0027.
EPR study of gamma-irradiated N-methyl-L-alanine,DL-2-methyl glutamic acid hemihydrate and Di-leucine hydrochloride in solid state
(Elsevier Science Bv, 2017) Sütçü, Kerem; Osmanoğlu, Yunus Emre
In this study, it was aimed to investigate (sic)-irradiated powders of N-methyl-L-alanine (NMLA), DL-2 methyl glutamic acid hemihydrate (DL2MGAH), and Di-leucine hydrochloride (DLHCI) at room temperature by electron paramagnetic resonance spectroscopy. After they-irradiation the samples indicated the existence of the CH3CNHCH3COOH, HOOCCH3NH2CCHCH2COOH1/2H(2)0 and (CH3)(2)CCH2CH NHCOOHCOCH (NH2HCI) CH2CH (CH3)(2) radicals, respectively. The spectral parameters of the radicals were determined. The results were compared with the earlier studies and discussed accordingly. (C) 2017 Elsevier B.V. All rights reserved.
Temperature behaviour studies on antipsychotic drug Olanzapine
(Elsevier Science Bv, 2017) Erdamar, Işık Yeşim Dicle
The antipsychotic drug Olanzapine in powder form was Co-60 gamma irradiated to investigate in various temperature value. The Electron Paramagnetic Resonance (EPR) spectrum of the irradiated Olanzapine, characterized by g = 2.0030, exhibits an intensity distribution 1:2:1. The room temperature EPR spectra of gamma irradiated Olanzapine was recorded in DMSO solution at frozen state. Temperature behavior of Olanzapine discussed by means of similarities and differences of EPR parameters. Kinetic decay features of radicals induced by gamma irradiation of Olanzapine were also studied. EPR experiments indicated that Olanzapine contained stable free radical species after irradiation and the intensity of the signal is increasing with the absorbed doses suggesting increasing radical concentration in the system. (C) 2017 Elsevier B.V. All rights reserved.
Phosphorus-nitrogen compounds. part 38. Syntheses, characterizations, cytotoxic, antituberculosis and antimicrobial activities and DNA interactions of spirocyclotetraphosphazenes with bis-ferrocenyl pendant arms
(Elsevier Science Sa, 2017) Elmas, Gamze; Okumuş, Aytuğ; Cemaloğlu, Reşit; Kılıç, Zeynel; Çelik, Süheyla Pınar; Açık, Leyla; Tunalı, Beste Cağdaş
The reactions of N4P4Cl8 (1), with two equimolar amounts of N-(1-ferrocenylmethyl)-N-methyl-propylenediamine gave the monoferrocenyl-spiro (as a byproduct), bisferrocenyl-2-trans-6-dispiro (2) and bisferrocenyl-2-cis-6-dispiro (3) cyclotetraphosphazenes. The 2-trans-6-dispiro (2) was reacted with excess monoamines to produce the tetraamino products (2a-2d). The one equimolar amount of the diamines and dialkoxides with 2 afforded the mono-diamino (2e and 2f) and mono-dialkoxy (2g and 2h) cyclotetraphosphazenes. Whereas, excess diamines and dialkoxides with 2 produced the bis-diamino (2i and 2j) and bis-dialkoxy (2k and 2l) bisferrocenyl-2-trans-6-dispirocyclotetraphosphazenes. The structures of the compounds were verified by elemental analyses, ESI-MS, FTIR, HSQC, HMBC, H-1, C-13, and P-31 NMR techniques. The molecular structures of 2 and 2b were established by X-ray crystallography. Compounds 2e and 2f have two stereogenic P-atoms. Additionally, the structures of 2i-2l containing tetraspiro rings in the skeletons look similar a propeller. The Fc groups of the cyclotetraphosphazenes were found to be redox active with two-reversible electron oxidations. The antimicrobial activity of the compounds was examined against some bacteria and yeast strains. The interactions of the compounds with DNA revealed that the compounds caused conformational changes even strand break on super-coiled DNA helix. Furthermore, the compounds (except 2, 2a and 2d) inhibited DNA restriction indicating compounds binding to A/A and G/G nucleotides of the DNA. The evaluations of the cytotoxic activity against L929 fibroblast and DLD-1 colon cancer cell lines were carried out. Some of the compounds were evaluated for antituberculosis activity against reference strain Mycobacterium tuberculosis H37Rv, and 2i and 2l displayed antituberculosis activity against H37Rv. (C) 2017 Elsevier B.V. All rights reserved.
A study to identify and analyze the radiosensitivity of 4-piperidinecarboxylic acid using electron paramagnetic resonance spectroscopy
(Springer Wien, 2024) Sütçü, Kerem
This study aims to investigate the spectroscopic, dosimetric, and stability properties of free radicals generated within 4-piperidinecarboxylic acid (4PCA) sample due to gamma irradiation within the 2-20 kGy range, utilizing electron paramagnetic resonance (EPR) spectroscopy. To achieve this goal, the EPR signals of the samples were studied in relation to microwave power, ranging from 0.01 to 50 mW, at room temperature. The investigation revealed that gamma-irradiation induces the formation of -CH2CCH2CH2- (radical I) and -CHN- (radical II) radicals within the 4PCA compound. Hyperfine structure constants and g values were also determined for the radicals. The optimal agreement between experimental and computed results within the dose range of 2-20 kGy was achieved using polynomial and linear functions. Experimental measurements were undertaken under varied temperature conditions (123-323 K) to study the dosimetric features of free radicals generated as a consequence of gamma irradiation. Furthermore, an investigation into the time dependency of signal intensity within the irradiated sample was conducted, with the objective of analyzing the long-term stability characteristics of the free radicals present.
Synthesis, characterization, and application of silver nanoparticle-thiophenol nanocomposite film on the glassy carbon surface
(Wiley, 2013) Güzel, Remziye; Ekşi, Haslet; Üstündağ, Zafer; Solak, Ali Osman
In this study, 4-thiophenol modified glassy carbon electrode was prepared by the reduction of 4-diazothiophenol tetrafluoroborate salt. Silver nanoparticles were attached to the thiophenol modified surface to prepare a thiophenol-silver nanoparticle composite film. 4-Aminothiopenol molecules were deposited by self-assembling technique to form multi-layered nanofilms of TP/SNP/PhNH2 on glassy carbon substrate. These surfaces were characterized by cyclic voltammetry, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, reflectance-absorption infrared spectroscopy, and ellipsometry at each multilayer film growth process. Atomic force microscopic images of GC/TP/SNP/PhNH2 surfaces were also acquired. The characterization methods show that the amine group containing surface permits the subsequent modification by a variety of coupling reactions for the immobilization of more complex systems. An application of the electrode modification for the determination of uric acid with a significantly lower detection limit is described. Copyright (c) 2013 John Wiley & Sons, Ltd.
Complexation studies of some newly synthesized precursors for substituted dibenzo and dibenzodiaza crown ethers
(John Wiley & Sons Inc, 2004) Çakır, Ümit; Uğraş, Halil İbrahim; Temel, Hamdi; Topal, Giray; 0000-0002-7056-3912; 0000-0001-9225-7425; 0000-0002-9430-4069
This study represents the synthesis of dibenzo and dibenzodiaza crown ether precursors with various functional groups in good yield by employing four different methods using polar protic and aprotic solvents with high boiling points. Also the complexation abilities of all synthesized ligands with Cu2+, Zn2+, and Ag+ were studied by conductometry; thus the conductometric behavior of Cu(NO3)(2), ZnCI2, and AgNO3 in 80% dioxane-water mixture was investigated in the presence of these ligands. The order of formation constant for complexes of the ligands with Cu2+, Zn2+, and Ag+ ions was found to be: Cu2+ > Zn2+ > Ag+ for the ligands of VI, VIL XI, and XII; Cu2+ > Ag+ > Zn2+ for the ligands of III and VIII; and Zn2+ > Cu2+ > Ag+ for the ligands of I, II, IV, V, IX, and X. (C) 2003 Wiley Periodicals, Inc.
Removal of Pb2+, Cd2+, and Cu2+ from phosphoric acid solution using the chitosan-modified natural zeolite
(Wiley-Blackwell, 2015) Kussainova, M. Z.; Chernyakova, R. M.; Dzhusipbekov, U. Z.; Paşa, Salih; Temel, Hamdi; 0000-0003-1243-3527; 0000-0002-4792-8821
Sorption ability of the chitosan-modified natural zeolite for Pb2+, Cd2+, and Cu2+ cations was investigated. The influence of time and concentration of heavy metals on their sorption from concentrated (85% H3PO4) phosphoric acid was determined. At 20 and 40 min of sorption curves, there are a number of maxima probably due to desorption of cations from the sorbent into the acid. According to the results, sorption of the modified zeolite for lead cation is the least in the whole interval of time. In the case of equal concentrations of all cations (C-Pb = C-Cd = C-Cu), sorption of lead, cadmium, and copper was 94.81-95.09%, 96.55-97.50%, and 97.53-98.14%, respectively. Sorption curves in the case of equal Pb2+ and Cd2+, but higher concentrations of Cu2+, are the same for all cations. Sorption of cadmium varies from 95.48% to 97.55%. Copper and lead sorbed in a less amount, in the case of (C-Pb = C-Cd = C-Cu), their sorption in 10 min was 95.42% and 97.55%, respectively. As in the case of equal concentrations of all cations (C-Pb = C-Cd = C-Cu), the sorptions of copper, cadmium, and lead were (92.09-96.93%), (92.13-95.37%), and (91.35-94.45%), respectively, in the case of (C-Cb = C-Cu < C-Cd). Physico-chemical methods of analysis are as follows: Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray powder diffraction patterns, and Brunauer-Emmett-Teller have shown that natural zeolite is activated without destroying the structure and adsorbs lead, as well as cadmium and copper cations. (C) 2015 Curtin University of Technology and John Wiley & Sons, Ltd.
Using grape pulp as a new alternative biosorbent for removal of a model basic dye
(Wiley-Blackwell, 2014) Sayğılı, Hasan; Sayğılı, Gülbahar Akkaya; Güzel, Fuat; 0000-0001-9860-503X; 0000-0002-8705-4372; 0000-0003-4900-8268
In the present study, grape pulp (GP), an agricultural waste available in large quantity in Turkey, was utilized as novel low-cost biosorbent to remove model basic dye [methylene blue (MB)] from aqueous solution by biosorption. The effects of various parameters including solution pH, biosorbent dosage, initial dye concentration, contact time, temperature and ionic strength on the biosorption process were investigated. The biosorption kinetic data were modeled using the pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic equations. Batch kinetic experiments showed that the biosorption fitted the pseudo-first-order kinetic model well with correlation coefficients greater than 0.98 in the temperature range 20-60 degrees C. The equilibrium biosorption data were analyzed by Langmuir, Freundlich and Temkin isotherm models. The results indicated that the Langmuir model provided the best correlation with the experimental data. The maximum biosorption capacities of GP for MB determined with the Langmuir model (q(m)) were 78.74, 116.28 and 153.85 mg g(-1) at temperatures of 20, 40 and 60 degrees C, respectively. The calculated thermodynamic parameters, namely, Delta G(0) (-5.33 to -7.17 kJ/mol), Delta H-0 (8.09 kJ/mol) and Delta S-0 (45.75 kJ/mol K), showed that the biosorption of MB on GP was spontaneous and endothermic under examined conditions. Results indicate that GP could be an alternative for more costly adsorbents used for MB removal. (c) 2013 Curtin University of Technology and John Wiley & Sons, Ltd.
The comparative reactions of 2-cis-4-ansa and spiro cyclotetraphosphazenes with difunctional ligands: Structural and stereogenic properties, electrochemical, antimicrobial and cytotoxic activity studies
(Wiley, 2021) Okumuş, Aytuğ; Elmas, Gamze; Kılıç, Zeynel; Binici, Arzu; Ramazanoğlu, Nagehan; Açık, Leyla; Çoşut, Bünyemin; Güzel, Remziye; 0000-0002-2169-5695; 0000-0003-4877-3697; 0000-0003-1061-8122; 0000-0001-7470-4156; 0000-0003-0541-9129; 0000-0002-3672-8429; 0000-0001-6530-0205; 0000-0002-5781-6049
In this study, two kinds of compounds, namely, mono-ferrocenyl-2-cis-4-dichloro-ansa- (2,4-ansa; 3) and mono-ferrocenyl-spiro- (spiro; 4) hexachlorocyclotetraphosphazenes, were obtained by the Cl replacement reaction of N4P4Cl8 (1) with an equimolar amount of sodium 3-(N-ferrocenylmethylamino)-1-propanoxide (2). The reactions of 2,4-ansa (3) with excess diamines and dialkoxides resulted in the formation of ansa-cyclotetraphosphazenes (3a-3e). Spiro (4) was reacted with excess diamines and dialkoxides to give the mono-ferrocenyl-spiro-cyclotetraphosphazenes (4a-4d). Although 2,4-ansa (3) produced the dispiro (3a) with N-(4-fluorobenzyl)-N '-methylethane-1,2-diamine, it afforded both monospiro (3b) and dispiro (3c) with N-(4-fluorobenzyl)-N '-methylpropane-1,3-diamine. However, spiro (4) yielded a trispiro (4a) with N-(4-fluorobenzyl)-N '-methylethane-1,2-diamine and 2,6-dispiro (4b) with N-(4-fluorobenzyl)-N '-methylpropane-1,3-diamine. The structures of the phosphazenes were elucidated by FTIR, ESI-MS and/or HRMS, spectroscopic and crystallographic (for 3f and 4b) data. Furthermore, the electrochemical findings of cyclotetraphosphazenes exhibited electrochemically reversible one-electron oxidation of Fe-redox centre. As an example, the chirality of 3c was investigated by P-31 NMR spectroscopy on the addition of (R)-(+)-2,2,2-trifluoro-1-(9 '-anthryl)-ethanol, chiral solvating agent (CSA). The circular dichroism (CD) (for 3d and 3e), HPLC (for 3d, 3e and 3f) and X-ray (for 3f) display that these compounds have chirality (RS ' or SR ') in the solution and solid state. This paper also focuses on the antimicrobial activities, the interactions with pBR322 DNA, in vitro anticancer activity against L929 fibroblast and MCF7 breast cells, and antituberculosis activity against Mycobacterium tuberculosis H37Rv of the cyclotetraphosphazenes.
Fractionation of partially stereoregular poly(propylene oxide) from acetonitrile solution
(Vch Publishers Inc, 1996) Çolak, Nureddin; Akgün, Abuzer; 0000-0002-3966-4483
Partially stereoregular poly(propylene oxide) (PPO) samples synthesized using Pruitt-Bagett catalysts (PBC) were fractionated at 40 degrees C and 70 degrees C from acetonitrile solution by adding small portions of water. The formed polymer-rich phases were clear liquids except the first three fractions obtained at 40 degrees C; those were solids. The fractions were characterized with their viscosity average molecular masses and melting points. Results showed that the procedure described in the present report fractionates partially stereoregular PPO on the basis of molecular weight, independent of their tacticity.
New reproducing kernel functions
(Hindawi Publishing Corporation, 2015) Akgül, Ali
Some new reproducing kernel functions on time scales are presented. Reproducing kernel functions have not been found on time scales till now. These functions are very important on time scales and they will be very useful for researchers. We need these functions to solve dynamic equations on time scales with the reproducing kernel method.

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