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Öğe Amide-based tripodal receptors for selective anion recognition(Springer, 2010) Ozturk, Gulsen; Colak, Mehmet; Togrul, MahmutIn order to improve efficiency and reduce waste production; the microwaves offer mild methods to prepare amides based neutral tripodals receptors directly from non activated carboxylic acids and amines in the absences of coupling reagents and solvents, with high yield and very short time. The preliminary 1H NMR titration experiments revealed that tripodals receptor 1 and 2 can recognize H2PO4 (-) and C6H5CO2 (-) through a 1:1 binding-stoichiometry in preference over other anions (PF6 (-), ClO4 (-), HSO4 (-) and Br-). The tripodal receptor 2 showed higher binding to the all examined anions than the tripodal receptor 1.Öğe Associations of alveolar bone loss and interleukin-1 levels in one- and two-stage surgical procedures: a randomized prospective trial(Taylor & Francis Ltd, 2017) Yildirim, Tuba Talo; Kaya, Filiz Acun; Yokus, Beran; Colak, Mehmet; Kaya, Eylem Ozdemir; Tekin, Giray; Saribas, EbruObjective: Dental implants have been widely and successfully used in recent years as an alternative treatment for removable and fixed dental prostheses. The aim of this randomized prospective study was to determine the alveolar bone loss rate (ABLR) and IL-1 levels in one- and two-stage surgical procedures.Materials and methods: This study included 40 patients with a single missing tooth in the posterior mandible; dental implants were inserted using a one-stage surgical procedure (Group I) or a two-stage surgical procedure (Group II). All clinical periodontal parameters were recorded; peri-implant crevicular fluid (PICF) samples were collected before loading (T0) and during the third (T1) and sixth (T2) months after loading. ABLR values were evaluated at T0 and T2 by using dental tomography. PICF was analysed after T2 samples were collected. The study was registered through clinicaltrials.gov; identifier NCT03045458.Results: This study found that, the probing pocket depth was found to be significantly higher in Group I than Group II at both T1 and T2 (p<.05). There was no significant difference in other clinical parameters between the groups (p>.05). There was a significant difference between Group I ABLR values at T0 and T2 (p<.05). The PICF IL-1 levels were not significantly different between groups (p>.05).Conclusions: Within the limitations of the short observational period and small sample size of this study, two-stage implant placement shows comparable clinical outcomes to implants placed using a one-stage placement protocol.Öğe C2-Symmetric chiral diamine ligands for enantiomeric recognition of amino acid esters and mandelic acid by proton NMR titration method(Tubitak Scientific & Technological Research Council Turkey, 2013) Aral, Hayriye; Aral, Tarik; Colak, Mehmet; Ziyadanogullari, Berrin; Ziyadanogullari, RecepTwo novel C-2-symmetric chiral diamines containing alpha-phenylethyl and alpha-(1-naphthyl)ethyl chiral subunits were prepared with quantitative yields. Enantiomeric recognition properties of these simple structured diamine ligands towards D- and L-amino acid esters and D- and L-mandelic acid were examined by the H-1 NMR titration method. These ligands exhibited strong complexation (with K-f up to 2481 M-1) and good enantioselectivity (up to K-L/K-D = 4.08) towards the mandelic acid enantiomers. The results show that simple structured and easily accessible acyclic C-2-symmetrical compounds can also be used for enantiomeric recognition of racemic amino acids and mandelic acid in addition to complex molecules such as crown ethers and other cyclic molecules.Öğe Complexation and transport of amino acid esters and their salts with synthesised chiral novel aza crown ether derivatives(Taylor & Francis Ltd, 2014) Kazaylek, Mehmet; Kocakaya, Safak Ozhan; Oral, Elif Varhan; Colak, Mehmet; Karakaplan, MehmetThe syntheses of four aza-15-crown-5 ethers bearing phenyl and phenoxymethyl moieties attached to a stereogenic centre on the crown ring were achieved. Macrocycles have exhibited strong binding ability (K-a=5364-12,969M(-1)) and modest enantiomeric discrimination towards the enantiomers of amino acid methyl ester salts by UV titration method in CHCl3 at 25 degrees C. Computer modelling results supported experimental data providing a detailed understanding of the molecular recognition mode between hosts and guests and the likely binding sites involved. Macrocycles were used for chiral discrimination of amino acids in their zwitterionic forms or as potassium and sodium salts in transport experiments across a bulk chloroform membrane with satisfactory selectivity.Öğe A cone-beam computed tomography study of root canal morphology of maxillary and mandibular premolars in a Turkish population(Taylor & Francis Ltd, 2014) Ok, Evren; Altunsoy, Mustafa; Nur, Bilge Gulsum; Aglarci, Osman Sami; Colak, Mehmet; Gungor, EnesAim. The aim of this study was to evaluate the root canal number and configuration of maxillary and mandibular premolar teeth by gender, intervals for decades, tooth position and unilateral or bilateral occurrence in a Turkish population using Cone Beam Computed Tomography(CBCT) scanning. Methodology. CBCT images of 5496 maxillary and mandibular premolars from 849 patients were evaluated. The following was evaluated in all the images: numbers of roots and root canals, the morphology of the root canal configuration according to the Vertucci classification, male-female differences in the tooth position and male-female differences in unilateral or bilateral occurrence. The reliability data were analyzed with a chi-square test. Results. The most prevalent root canal frequency was the two canals (86.2%) and type IV (76.9%) configuration for maxillary first premolar, one canal (59.7%) and type I (54.5%) canal configuration for second premolar. The incidence of one canal was higher in females and the occurrence of two or three canals was more common in males. The incidence of one canal was higher on the left side of maxillary premolars and the incidence of two canals was higher on the right side. Most mandibular first (93.5%) and second (98.5%) premolars had one canal. In general, females had one root canal of the mandibular premolar, whereas males had two or three canals. The type I configuration was most common and the incidence was higher on the right side. There were some differences found in the frequency distribution of the number of root canals and configuration of maxillary and mandibular premolar teeth according to intervals for decades. Conclusion. CBCT scanning provides comprehensive information about the root canal morphology of maxillary and mandibular premolar teeth. These data may help clinicians in root canal treatment of premolar teeth.Öğe The effect of demographic and disease variables on Schneiderian membrane thickness and appearance(Elsevier Science Inc, 2017) Yildirim, Tuba Talo; Guncu, Guliz Nigar; Goksuluk, Dincer; Tozum, Melek Didem; Colak, Mehmet; Tozum, Tolga FikretObjectives. The purpose of this study was to evaluate the prevalence of sinus mucosal thickening (MT) and mucosal appearance (MA) in a patient population as detected with cone beam computed tomography (CBCT) and to determine the effects of various disease and demographic factors on MT and MA. Study Design. The retrospective study consisted of CBCT images of 1000 maxillary arches in 500 patients. The arches were divided into 3 groups (atrophic, partially atrophic, and nonatrophic) according to the type of the maxillary dental crest. The CBCT scans were assessed to detect the prevalence of maxillary sinus MT and MA. chi(2) analysis was used to determine the significance of association of periodontal bone loss (PBL), periapical (PA) status, alveolar crest type, age, and gender on sinus MT and MA. Results. MT was significantly associated with PBL (P = .004), PA status (P = .001), and gender (P < .01). MA was significantly associated with PBL (P = .038), PA status (P = .009), and gender (P < .020). There were no significant associations between age or crest type and either MT or MA. Conclusions. Periodontal bone loss, PA lesions, and gender may have an association with MT of the maxillary sinus.Öğe Enantioselective nitroaldol (Henry) reaction catalyzed by chiral Schiff-base ligands(Pergamon-Elsevier Science Ltd, 2008) Colak, Mehmet; Demirel, NadirChiral Schiff-bases 2, 3, 4 and 5 were designed for the enantioselective nitroaldol (Henry) reaction. The highest enantioselectivity was observed for ligand 4 (82% ee) when CH2Cl2 was used as a solvent. (C) 2008 Elsevier Ltd. All rights reserved.Öğe Evaluation of technical quality and periapical health of root-filled teeth by using cone-beam CT(Univ Sao Paulo Fac Odontologia Bauru, 2014) Nur, Bilge Gulsum; Ok, Evren; Altunsoy, Mustafa; Aglarci, Osman Sami; Colak, Mehmet; Gungor, EnesObjective: This study aimed to assess the quality of root fillings, coronal restorations, of all root-filled teeth and their association with apical periodontitis (AP) detected by cone-beam computed tomography (CBCT) images from an adult Turkish subpopulation. Material and Methods: The sample for this study consisted of 242 patients (aging from 15 to 72 years) with 522 endodontically treated teeth that were assessed for technical quality of the root canal filling and periapical status of the teeth. Additionally, the apical status of each root-filled tooth was assessed according to the gender, dental arch, tooth type and age classification, undetected canals, instrument fracture, root fracture, apical resorption, apical lesion, furcation lesion and type and quality of the corona! structure. Statistical analysis was performed using percentages and chi-square test. Results: The success rate of the root canal treatment was of 54.4%. The success rates of adequate and inadequate root canal treatment were not significantly different (p>0.05). Apical periodontitis was found in 228 (45.6%) teeth treated for root canals. Higher prevalence of AP was found in patients aging from 20 to 29 years [64 (27%) teeth] and in anterior (canines and incisors) teeth [97 (41%) teeth]. Conclusions: The technical quality of root canal filling performed by dental practitioners in a Turkish subpopulation was consistent with a high prevalence of AP. The probable reasons for this failure are multifactorial, and there may be a need for improved undergraduate education and postgraduate courses to improve the clinical skills of dental practitioners in endodontics.Öğe Evaluation of the relationship between the maxillary posterior teeth and the sinus floor using cone-beam computed tomography(Springer France, 2014) Ok, Evren; Gungor, Enes; Colak, Mehmet; Altunsoy, Mustafa; Nur, Bilge Gulsum; Aglarci, Osman SamiThe aim of this study was to evaluate the relationship between each root of maxillary premolars and molars and the maxillary sinus floor according to sex, sinus position, and age by decade in a Turkish population by using cone-beam computed tomography (CBCT) scanning. We evaluated a database of 5,166 (2,680 maxillary premolars and 2,486 maxillary molars) CBCT scans obtained from 849 patients. The vertical relationship between each root of the molar and premolar teeth to the sinus floor was classified into three types: type 1, the roots penetrated into the sinus floor; type 2, the roots contacted the sinus floor; and type 3, the roots extended below the sinus floor. The results of the classification of each root in relationship to the sinus floor were as follows: type 3 occurred most frequently in the first (92.4 %) and second (71.6 %) premolar teeth, type 1 (34.2 %) occurred most frequently in the palatinal roots of the first molar teeth, type 3 occurred most frequently in the mesiobuccal (39.9 %) and distobuccal (39.7 %) roots of the first molar teeth, and type 2 (36.7 %) occurred most frequently in the mesiobuccal roots of the second molar teeth. No significant differences were found between the left and right sides, but several differences were found between males and females. The relationship between the posterior teeth and the sinus floor differed according to the age decade interval (p < 0.05). The maxillary first premolars have no relationship with the maxillary sinus floor, but the maxillary second molars are closer to the sinus floor. Also the second decade and males were most susceptible to undesirable results.Öğe Novel bis(aminoalcohol)oxalamide organogelators and their diglycolylamide analogs: evaluation of gelation efficiency in various organic fluids(Tubitak Scientific & Technological Research Council Turkey, 2017) Colak, Mehmet; Baris, Deniz; Pirinccioglu, Necmettin; Hosgoren, HalilThree modular types of bis(aminoalcohol)oxalamides (1, 4, and 7) and bis(aminoalcohol)diglycolylamide (8) gelators have been prepared by the reaction of the respective aminoalcohols with oxalyl and digycolyl methylesters as potential low-molecular-weight organogelators. The gelation properties of these amides have been evaluated in various aromatic organic solvents (xylene, toluene, isopropyl benzene, and aromatic ether type organic fluids such as anisole or alpha-phenylethylmethylether) as well as the long-chain aliphatic alcohols (1-hexanol, 1-octanol, 2-octanol, and aromatic 1-phenylethanol). The compounds with sec-butyl and ethyl side chains produce good gelation properties in both aromatic and other organic fluids. Furthermore, the common oxalamide linker present in the gelators was replaced by an extended diglycolylamide linker (8) and its behaviors were compared with the benzylic oxalamide analog (3). The gelator (8) gives the best results with aromatic fluid and lauric acid ethyl ester. H-1 NMR studies reveal the existence of temperature dependent network assembly/dissolution equilibrium and produce K-gel. FTIR was employed to see the effect of hydrogen bonding in the formation of gel network. Thermodynamic parameters regarding gel-to-sol transition were collected with van't Hoff relationships.Öğe Root canal morphology analysis of maxillary permanent first and second molars in a southeastern Turkish population using cone-beam computed tomography(Elsevier Taiwan, 2015) Altunsoy, Mustafa; Ok, Evren; Nur, Bilge Gulsum; Aglarci, Osman Sami; Gungor, Enes; Colak, MehmetBackground/purpose: The aim of this retrospective study was to determine the root and canal morphology of the maxillary first and second molars in a Turkish subpopulation using cone-beam computed tomography (CBCT). Materials and methods: CBCT images of 417 women and 410 men aged 14-70 years were examined. A total of 1158 maxillary permanent first molars and 1305 maxillary permanent second molars were analyzed. The number of root canals and canal configurations were investigated and classified according to Vertucci's classification. The data were analyzed using Pearson's Chi-square test. Results: In both first and second maxillary molars, the presence of three roots was the most common occurrence. The prevalence of additional canals (type II, Ill, or greater) in mesiobuccal roots of maxillary first and second molars was approximately 62% and 37.5%, respectively. Type I canal configuration was the most prevalent in the distobuccal (99.6%) and palatal (99.8%) roots of maxillary first molars, and in the distobuccal (99.7%) and palatal (99.2%) roots of maxillary second molars. The incidence of the number of root canals and the configurations of maxillary first and second molars did not statistically differ with sex (P > 0.05). Conclusion: The high prevalence of additional canals in the mesiobuccal roots of maxillary first and second molars is noteworthy. CBCT is an effective method to study the external and internal morphology of dental tissues. Copyright (C) 2014, Association for Dental Sciences of the Republic of China. Published by Elsevier Taiwan LLC. All rights reserved.Öğe Solid phase extractive preconcentration of trace metals using p-tert-butylcalix[4]arene-1,2-crown-4-anchored chloromethylated polymeric resin beads(Elsevier, 2007) Seyhan, Serap; Colak, Mehmet; Merdivan, Melek; Demirel, Nadir5,11,17,23-Tetrakis(1,1-dimethylethyl)-25,26-dihydroxy-27,28-crown-4-calix[4]arene in the cone conformation was synthesized. This p-tertbutylcalix[4]arene-1,2-crown-4 compound was then anchored with Merrifield chloromethylated resin beads. The modified polymeric resin was characterized by H-1 NMR, FT-IR and elemental analysis and used successfully for the separation and preconcentration of Cu(II), Cd(II), Co(II), Ni(II) and Zn(II) prior to their determination by FAAS. Effective extraction conditions were optimized in both batch and column methods. The resin exhibits good separating ability with maximum between pH 6.0-7.0 for Cu(II), pH 6.0 for Cd(II), pH 5.0 for Co(II), pH 4.0-4.5 for Ni(II), and pH 4.5 for Zn(H). The elution studies were carried out with 0.5 mol L-1 HCL for Cu(II), Co(II) and Co(II), 1.0 mol L-1 HCl for Cd(II) and Zn(II). The sorption capacity, preconcentration factor and distribution coefficient of each metal ion were determined. The detection limits were 1.10, 1.25, 1.83, 1.68 and 2.01 mu g L-1 for Cu(II), Cd(II), Co(II), Ni(II) and Zn(II). The influence of several ions on the resin performance was also investigated. The validity of the proposed method was checked for these metal ions in NIST standard reference material 2709 (San Joaquin Soil) and 2711 (Montana Soil). (c) 2006 Elsevier B.V. All rights reserved.Öğe Synthesis of new diaza-18-crown-6 ethers derived from trans-(R,R)-1,2-diaminocyclohexane and investigation of their enantiomeric discrimination ability with amino acid ester salts(Pergamon-Elsevier Science Ltd, 2013) Karakaplan, Mehmet; Ak, Devran; Colak, Mehmet; Kocakaya, Safak Ozhan; Hosgoren, Halil; Pirinccioglu, NecmettinThe synthesis of four diaza-18-crown-6 ethers with C-2-symmetry derived from trans-(R,R)-1,2-diaminocyclohexane bearing methyl, phenyl and phenoxymethyl moeities attached to a stereogenic centre on the crown ring were achieved. Enantiomeric discrimination of these macrocycles against amino acid methyl ester salts was examined by H-1 NMR titration method. They exhibit strong binding ability and some of them show a very high enantioselectivity towards amino acid esters, corresponding to 537 kJ/mol of binding energy difference in CDCl3 at 25 degrees C. Computational modelling showed parallel results with experimental calculations, thus providing a detailed understanding of molecular recognition mode and binding sites between the hosts and the guests. (C) 2012 Elsevier Ltd. All rights reserved.Öğe Synthesis of novel chiral Schiff-base ligands and their application in asymmetric nitro aldol (Henry) reaction(Pergamon-Elsevier Science Ltd, 2007) Colak, Mehmet; Aral, Tarik; Hosgoeren, Halil; Demirel, NadirChiral Schiff-bases prepared from chiral amino alcohols catalyze the enantio selective Henry (nitro aldol) reaction between nitromethane and p-nitrobenzaldehyde in the presence of Cu(OTf)(2) and Zn(OTf)(2). Zn(OTf)(2) promoted the reaction yield, while Cu(OTf)(2) promoted the enantiomeric excess. The highest enantioselectivities were observed with ligand 3 (44% ee) and ligand 5 (47% ee). (C) 2007 Elsevier Ltd. All rights reserved.Öğe Three-dimensional evaluation of maxillary sinus volume in different age and sex groups using CBCT(Springer, 2019) Belgin, Ceren Aktuna; Colak, Mehmet; Adiguzel, Ozkan; Akkus, Zeki; Orhan, KaanAim Sinus maxillaris is an important anatomical formation in many branches of dentistry due to its proximity to the field of work. Various methods have been used in literature to measure the maxillary sinus volume (MSV) such as cadavers, stereology, two-dimensional conventional radiographs, computed tomography (CT), magnetic resonance imaging (MRI). The aim of this study is to evaluate the change of maxillary sinus volume according to age and gender with MIMICS 19.0 (Materialise HQ Technologielaan, Leuven, Belgium) which is one of three-dimensional modeling software. Materials and methods This study was performed in 200 patients selected by a retrospective review of the archives of the Dicle University, Faculty of Dentistry, Department of Oral and Maxillofacial Radiology. Patients were divided into five age groups (18-24 years, 25-34 years, 35-44 years, 45-54 years, and >= 55 years) and by sex. Cone-beam computed tomography (CBCT) images of the patients were transferred to the MIMICS software and the MSV was measured. All statistical analyses were performed using the SPSS (Statistical Package for Social Sciences, version 21) software. Results There was no statistically significant difference between the right and left maxillary sinus volume according to the findings obtained from our study, and maxillary sinus volume in males was found to be significantly higher than that of females. Another finding of our study is that the maxillary sinus volume decreases with age increase. Especially it was also found that the sinus volume in males in the 18-24 age group was statistically significantly higher than females. Conclusion Consequently, maxillary sinus volume measurements can be made on CT, CBCT, MRI scans using reconstruction software.Öğe Two-component organogelators: combination of N?-alkanoyl-L-lysine with various N-alkanoyl-L-amino acids: additional level of hierarchical control(Taylor & Francis Inc, 2018) Colak, Mehmet; Baris, Deniz; Evcil, Murat; Demirel, Nadir; Hosgoeren, HalilSynthesis of two-component organogelation system was performed very easy and concise manner from N-epsilon-palmitoyl-L-lysine ethyl ester and N-epsilon-miristoyl-L-lysine ethyl ester in which they were used as base component and N-lauroyl-L-amino acids (amino acids:, alanine, leucine and phenylalanine as acid components.). And their organogelation properties were examined in different pharmaceutical fluids such as liquid paraffin, fatty acid ethyl, and isopropyl esters. In this way, gelation efficiency was ascertained variations of alkanoyl moieties and combination of different amino acids in the gelator structures. Characterization of gelators was performed via thermal measurement such as Tg and gel-sol enthalpy change; SEM and FTIR as optical methods.
