Matematik ve Fen Bilimleri Eğitimi Bölümü Koleksiyonu

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Nonlineer Schrödinger denkleminin tam çözümleri
(Siirt University, 2019) Gümüş, Halide; Yılmaz, Halis
Bu makale Nonlineer Schrödinger denklemine ayrılmıştır. Öncelikle denklem hakkında bilgiler verilmiş ve daha sonra denklem enerji korumalı yöntem ile elde edilmiştir. Sonraki bölümde de ilerleyen dalga çözümünü elde ettik ve daha sonra Hirota metodunu kullanarak NLS denkleminin 1-soliton ve 2-soliton çözümünü verdik. Sonuç ve tartışma kısmı da beşinci bölümde verilmiştir.
Fen bilgisi alanında sosyobilimsel konuların öğretimine yönelik yapılan tezlerin tematik analizi
(Dokuz Eylül Üniversitesi, 2024) Bilen, Duygu; Çapras, Gülsima
Bu araştırmanın amacı, fen eğitiminde sosyobilimsel konularla ilgili tezlerde ele alınan konulara kapsamlı bir bakış sunmak ve yapılan araştırmalardaki genel eğilimleri resmetmektir. Bu amaç doğrultusunda 2008'den 2022'ye kadar Türkiye'de fen eğitimi alanında sosyobilimsel konulara odaklanan 50 yüksek lisans ve 15 doktora tezi olmak üzere toplam 65 tez incelenmiştir. Tezlere Yükseköğretim Kurulunun (YÖK) ulusal tez merkezi veri tabanından erişim sağlanmıştır. Her bir tez; araştırmacılar tarafından geliştirilen ve a) çalışma yılı, b) tezin yapıldığı üniversite, c) tezin dili, d) araştırma konusu, e) araştırma katılımcıları, f) örneklem büyüklüğü ile örnekleme yöntemi, g) çalışma tasarımı, h) veri toplama araçları ve i) veri analiz teknikleri başlıklarını içeren tez inceleme formu kullanılarak gözden geçirilmiştir. Ardından veriler içerik analizine tabi tutulmuş ve ulaşılan sonuçlar frekans dağılımları, yüzdeler ve tablolar aracılığıyla özetlenmiştir. Ulaşılan sonuçlar sosyobilimsel konuların çoğunlukla yüksek lisans düzeyinde çalışıldığını ve yapılan tez sayısında 2019 yılından sonra artış yaşandığını göstermiştir. Tezlerde nitel araştırma yönteminin daha sık kullanıldığı belirlenmiş; buna paralel olarak verilerin toplanmasında çoğunlukla görüşme tekniğine başvurulduğu, tesadüfi olmayan örnekleme yöntemi ile 0-50 aralığındaki örneklem büyüklüğünün daha çok tercih edildiği saptanmıştır. Çalışmaların çoğunlukla üniversite öğrencileri üzerinde yürütüldüğü tespit edilmiştir. Sosyobilimsel konular hakkındaki tezler ele aldıkları konular açısından sınıflandırıldığında tutum öne çıkan araştırma konusu olarak bulunmuştur.
Matematik öğretmen adaylarının etkinlik tasarımında günlük yaşamla ilişkilendirmeyi yansıtmaya yönelik görüşleri, becerileri ve örnekleri
(Dokuz Eylül Üniversitesi, 2021) Çenberci, Selin; Özgen, Kemal
Bu araştırmanın amacı, matematik öğretmen adaylarının etkinlik tasarımında matematiği günlük yaşamla ilişkilendirmeyi kullanmalarına yönelik görüşlerini belirlemek ve etkinliklere matematiksel ilişkilendirme becerilerini yansıtma durumlarını incelemektir. Araştırmada betimsel araştırma yo¨ntemlerinden biri olan o¨zel durum c¸alıs¸ması kullanılmıs¸tır. Araştırmanın çalışma grubunu bir devlet üniversitesinin ilköğretim matematik öğretmenliği programında öğrenim görmekte olan ve etkinlik tasarlamaya yönelik ders alan 28 öğretmen adayı oluşturmaktadır. Öğretmen adaylarının matematiksel ilişkilendirmeye ilişkin görüşlerini daha derinlemesine ortaya çıkarmak amacıyla açık uçlu sorular hazırlanarak yarı yapılandırılmış görüş formu uygulanmıştır. Çalışma nitel araştırma olup veriler içerik analizi yardımıyla analiz edilmiştir. Elde edilen verilerin analizinde her bir problem için kategoriler belirlenmiştir. Çalışmanın sonucunda genel olarak matematik öğretmen adaylarının matematiksel öğrenme etkinliklerinin tasarımına günlük yaşamla ilişkilendirmeyi yansıtmaya yönelik görüşlerinin olumlu olduğu ancak bu konuda bazı zorluklar yaşadıkları tespit edilmiştir. Bu zorlukları aşabilmek için çaba harcadıklarına yönelik görüşlere sahip oldukları da ifade edilmektedir. Öğretmen adaylarının matematiksel etkinliklerin tasarımında, günlük yaşamla ilişkilendirmeyi yansıtma becerileri konusunda eksiklikleri olduğu sonucuna ulaşılmıştır.
Students’ proof construction through computer-supported collaborative learning: The perspectives of habermas’ theory of rationality and duval’s theory of registers of semiotic representation
(Springer, 2024) Urhan, Selin; Zengin, Yılmaz
This study aims to examine how students' performance in constructing and transforming representations during the proving of calculus rules unfolds in a computer-supported collaborative learning (CSCL) environment, within the context of rationality. The CSCL environment was designed by integrating the ACODESA method and dynamic mathematics software GeoGebra. The participants included 18 university students. The proofs and GeoGebra files of the participants and transcripts of arguments during the GeoGebra-integrated collaborative phases of ACODESA were analyzed based on Habermas' theory of rationality and Duval's theory of registers of semiotic representation. The students improved their proof in building a geometric representation (e.g., drawing a secant line on a constant function graph), and in the treatment within the algebraic register (e.g., during the expansion of (x+h)n)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${(x+h)}<^>{n})$$\end{document} in the context of epistemic rationality. They developed their proof in the conversion (e.g., drawing a secant line in the geometric register and hence obtaining algebraic representation of the derivative function) in the context of teleological rationality. The students provided more understandable proofs due to their improvement in the context of communicative rationality. The difficulties experienced by the students in building representations, treatment, and conversion could be analyzed with the combined application of Duval's theory of registers of semiotic representation and Habermas' theory of rationality. Based on the results of the study, it is suggested to design GeoGebra-integrated CSCL environments to support students' performance in constructing and transforming representations within the context of being rational during the teaching of proofs related to calculus concepts.
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.
E-learning in mathematics education: A bibliometric analysis(2012-2022)
(Anadolu Universitesi, 2024) Kaya, Deniz; Kutluca, Tamer
This study aims to create a comprehensive bibliometric map of published scientific articles on e-learning in mathematics education (ME). We used Web of Science (WoS) database to analyzed 341 articles published by 1018 authors representing 79 countries between 2012 and 2022. In this context, we examined scientific articles in terms of scientific production, network analysis, trend topics, thematic change, and conceptual structure. Bibliometric analysis was performed in the study. According to findings, the number of published articles differ according to the years, but the number of citations is constantly increasing. Albano, and Dello Iacono are the most prolific authors. The most productive institutions are Salerno and Black Sea Technical Universities. China, USA, and Russia lead the countries of the corresponding authors. According to the network analysis, the journals of Computers & Education and Computers in Human Behavior form strong links. The most used keywords are students, technology, and mathematics. The pandemic, covid, reality, and process are trend topic titles. It determined that the best size reduction obtained in the conceptual analysis constituted approximately 31% of the total variability. We presented some suggestions based on the findings obtained at the end of the research.
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.

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