Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Gul, Muhammet(82)
- Akkurt, Nevzat(67)
- Güler, Ömer(66)
- Baskonus, Haci Mehmet(62)
- Bulut, Hasan(60)
- Tekin, H.O.(52)
- ALMisned, Ghada(49)
- Yucesan, Melih(43)
- Yildirim, Numan(42)
- Yildirim, Nuran Cikcikoglu(38)
- Paksoy, Mehmet Yavuz(36)
- Serdar, Osman(36)
- Zengin, Gokhan(36)
- Ince, Muharrem(34)
- Celik, Erkan(33)
- Benzer, Fulya(32)
- Kocabaş, Mehmet(30)
- Sulaiman, Tukur Abdulkadir(30)
- Tanyol, Mehtap(29)
- Yildirim, Ozal(28)
- Aslan, Naim(26)
- Kök, Mediha(26)
- Özkul, İskender(26)
- Ates, Mehmet(25)
- Danabas, Durali(25)
- Kutluyer, Filiz(25)
- Can, Erkan(24)
- Kutlu, Banu(23)
- Onat, Onur(23)
- Demir, Veysel(22)
- Erten, Fusun(22)
- Guler, Omer(22)
- Say, Yakup(22)
- Güler, Seval Hale(21)
- Yaman, Mehmet(21)
- Baykal, Duygu Sen(20)
- Sançar, Taylan(20)
- Susam, Selim Orhun(20)
- Cakilcioglu, Ugur(19)
- Orhan, Cemal(19)
Yayınlar
- MakaleYalnız künye2013Scopus SJRQ3Microstructure and mechanical properties of PM Fe-Cu-Al2O3 alloys
Çelik, Ertugrul; Islak, Serkan; Kir, Durmus; Ilkiliç, Cumali
The purpose of this study was to investigate the effect of Cu addition on the microstructure and mechanical properties of PM Fe-Cu-Al2O3 alloys produced using hot-pressing method. Copper powder was added to iron powder at 5 wt.%, 10 wt.% and 15 wt.% rates. Production of Fe-Cu-Al2O3 alloys was carried out under pressure of 35 MPa, at 750, 800 and 850 degrees C, and for a sintering time of 4 minutes. Microstructure phase composition, relative density, hardness, and transverse rupture strength of the alloys were investigated. Phase composition and microstructure of the alloys were characterised by optical microscopy, X-ray diffraction and scanning electron microscope (SEM-EDS) techniques. The transverse rupture strength (TRS) of the samples was assessed by means of a three-point bending test. Hardness of Fe-Cu-Al2O3 alloys changed between 57 HB and 110 FIB depending on the amount of Cu and sintering temperature. Results show that the TRS of the alloys decreased together with the increase in the amount of copper, while it increased with increasing sintering temperature.
AtıfWoS2
İncele - MakaleAçık Erişim2013Scopus SJRQ2Total phenolic contents and free-radical scavenging activities of grape (Vitis vinifera L.) and grape products
Keser, Serhat; Celik, Sait; Turkoglu, Semra
Grape is one of the world's largest fruit crops, with an approximate annual production of 58 million metric tons, and it is well known that the grape skins, seeds and stems, waste products generated during wine and grape juice processing, are rich sources of polyphenols. It contains flavonoids, phenolic acids and stilbenes. In this study, we tried to determine antioxidant properties and phenolic contents of grape and grape products (fresh fruit, seed, dried fruit, molasses, pestil, vinegar) of ethanol and water extracts. Antioxidant properties of extracts were investigated by DPPH center dot, ABTS(center dot+), superoxide, H2O2 scavenging, reducing power, metal chelating activity and determination of total phenolic contents. The seed extracts revealed highest ABTS(center dot+), DPPH center dot, H2O2 scavenging and reducing power activities. Furthermore, these extracts showed higher total phenolic contents than other grape product extracts.
AtıfWoS41OpenAlex45
İncele - MakaleYalnız künye2013Scopus SJRQ3Effects of oral administrations of pomegranate seed extract on surgical wound healing in rabbits
Kandemir, F. M.; Sagliyan, A.; Ozkaraca, M.; Gunay, C.; Han, M. C.; Benzer, F.
This study examined the effects of orally given pomegranate seed extract (PSE) on healing of surgically induced full thickness skin wounds in terms of clinical, histopathological and biochemical aspects. A total of 48 healthy, adult male New Zealand rabbits were randomly divided in 2 equal experimental (PSE group) and control groups (C): one week prior the surgery, 100 mg/kg per day via gastric catheter pomegranate seed extract was orally given for 20 days to the assay animals. After one week, all rabitts were anaesthetized by intramuscular injection of xylazine HCl (5 mg/kg) and ketamine HCI (50 mg/kg) and after shaving and disinfection, a circular full thickness skin defect of 2.5 cm diameter was incised on the median line of the back area. Macroscopic and histopathological aspects as well as the tissue oxidant/antioxidant balance were determined on 6 rabbits from each group slaughtered at the 5th, 10th, 15th and 20th days post-surgery.
AtıfWoS9İncele - MakaleAçık Erişim2013Scopus SJRQ4Effects of the Different Methacrylate Monomers on Bond Strength Between Soft Liner and Acrylic Resin
Bolayir, Giray; Soygun, Koray; Simsek, Selcuk; Yilmaz, Ersen; Dogan, Arife; Boztug, Ali; Dogan, Orhan Murat
In the present study, tensile bond strength between on acrylic resin and a soft liner, molloplast B, was studied. To enhance the bonding capacity between these materials, acrylic resin surface was modified using ethyl methacrylate, iso-butyl methacrylate or tert-butyl methacrylate monomers. The monomers were applied onto the surfaces of methacrylate components for 60, 120 or 180 s and the bond strength values were obtained. The values were statistically compared. Changes on the modified surfaces were investigated by fourier transform infared spectroscopy with attenuated total reflectance (FTIR-ATR). The highest bond strength value was obtained from 120 s treatments with ethyl methacrylate and the lowest value was obtained from 60 s treatments with iso-butyl methacrylate. These high alkyl monomers also had secondary interactions on the acrylic surfaces, evidenced by FTIR-ATR.
AtıfOpenAlex1İncele - MakaleAçık Erişim2013Scopus SJRQ3ANTIMICROBIAL ACTIVITIES OF SOME EUPHORBIA SPECIES
Kirbag, Sevda; Erecevit, Pinar; Zengin, Fikriye; Guvenc, Ayse Nilay
In this study, the antimicrobial activities of methanolic extracts and latex of some Euphorbia species used for medical purposes in Turkey were investigated. The extracts of Euphorbia aleppica L., Euphorbia szovitsii Fisch.&Mey. var. harputensis Aznav. ex M. S. Khan, Euphorbia falcata L. sub. falcata var. falcata, Euphorbia denticulata Lam., Euphorbia macroclada Boiss., Euphorbia cheiradenia Boiss.&Hohen, Euphorbia virgata Waldst.&Kit., Euphorbia petiolata Banks&Sol. were prepared with methanol. The antimicrobial activities of these extracts were examined on test microorganisms as follows: Staphylococcus aureus COWAN 1, Bacillus megaterium DSM 32, Proteus vulgaris FMC 1, Klebsiella pneumonia FMC 5, Escherichia coli ATCC 25922, Pseudomonas aeruginosa DSM 50071, Candida albicans FMC 17, Candida glabrata ATCC 66032, Epidermophyton sp. and Trichophyton sp. by the disc diffusion methods and well agar method. The MIC values of extracts were determined according to the broth microdulitions method. Results indicated that extracts of Euphorbia species inhibited the growth of tested microorganisms in the different ratio. Also, the MIC values of extracts were determined as 31,2-1000 mu g.
AtıfWoS29OpenAlex30İncele - MakaleAçık Erişim2013Scopus SJRQ2RARE EARTH ELEMENT (REE) GEOCHEMISTRY AND GENESIS OF OIL SHALES AROUND DAGHACILAR VILLAGE, GOYNUK-BOLU, TURKEY
Çimen, Okay; Koç, Sukru; Sari, Ali
The study area is located in the south of Daghacilar village of Goynuk town in Bolu Province, Turkey. This study is a pioneering work in Turkey on the genesis and environmental characteristics of oil shales and other shallow marine-type sedimentary rocks regarding their major and rare earth element contents. The abundances of SiO2, Al2O3, TiO2, K2O and Fe2O3 decrease in the following order: claystone > oil shale > marl. CaO and MgO abundances are ranked in the decreasing order as follows: marl > oil shale > claystone. These results reveal the presence of two different genetic groups - detrital and marine. The same groups were also established in the correlation studies of elements. TOT/C and TOC contents of rocks observe the following order: oil shale > marl > claystone, and as a result of variations in redox conditions they also vary in a wide range. Total carbon and total organic carbon are positively correlated with the group representing clays and negatively correlated with CaO, MgO and MnO. That is why TOT/C and TOC are associated with clays. The positive correlations between some major oxides (e.g. SiO2, Al2O3, Fe2O3, TiO2 and K2O) and REE might indicate that clays and iron oxy-hydroxyls play an important role in transportation and deposition processes. The only slight negative Ce and positive Eu anomalies and Ce/Ce* and Eu/Eu* values recorded in the depositional environment indicate low oxygenated and anaerobic (reducing) conditions.
AtıfWoS6OpenAlex9İncele - MakaleAçık Erişim2013Scopus SJRQ1Optimal feature selection for classification of the power quality events using wavelet transform and least squares support vector machines
Eristi, Huseyin; Yildirim, Ozal; Eristi, Belkis; Demir, Yakup
In this paper, a new optimal feature selection based power quality event recognition system is proposed for the classification of power quality events. While Apriori algorithm is capable of processing categorical data, an effective feature vector, which represents distinctive features of digital power quality event data, has been obtained by means of the proposed k-means based Apriori algorithm feature selection approach. The proposed k-means based Apriori algorithm feature selection approach is presented with a power quality event recognition system. In the power quality event recognition system, normalization and segmentation processes have been applied to three-phase event voltage signals. Using 9-level multiresolution analysis, wavelet transform coefficients of the event signals have been obtained. By applying nine different feature extraction processes to these coefficients, a 90 dimensional feature vector belonging to three-phase event voltage signals has been extracted. Optimal feature vector has been obtained by applying the k-means based Apriori algorithm feature selection approach to the obtained feature vector, which has been applied as the last step to the input of the least squares support vector machine classifier and recognition performance results have been obtained. Real power quality event data have been used to evaluate the performance of the proposed feature selection approach and power quality event recognition system. According to the results, the proposed k-means based Apriori algorithm feature selection approach and power quality event recognition system are efficient, reliable and applicable and classify three-phase event types with a high degree of accuracy. (C) 2013 Elsevier Ltd. All rights reserved.
AtıfWoS98OpenAlex131İncele - MakaleAçık Erişim2013Scopus SJRQ4Bioaccumulation of Copper and Zinc in Freshwater Crayfish (Astacus leptodactylus) Fed with Zebra Mussels (Dreissena polymorpha) Collected from Keban Dam Lake, Turkey
Aksu, Onder; Gulec, Azime Kucukgul; Demir, Veysel; Danabas, Durali; Yildirim, Numan; Ozcelik, Mehtap; Can, Erkan; Kocabas, Mehmet
This study is aimed to determine the bioaccumulation of copper and zinc in hemolymph of freshwater crayfish (Astacus leptodactylus) fed with zebra mussel (Dreissena polymorpha) collected from Keban Dam Lake. This is the first study on bioaccumulation of Cu and Zn in hemolymph of males and females of A. leptodactylus. The average concentrations of Cu and Zn in the hemolymph samples were found out as 0.54 and 35.07 ppm respectively for male and 0.42 and 15.59 ppm respectively for female control freshwater crayfish. The levels of Zn in the hemolymph of both male and female ones among control and diet groups were statistically significant (P < 0.05). The Cu levels among control and diet groups in female ones were statistically significant (P < 0.05) but not in the male ones (P > 0.05). The results of current study revealed that feed treatment with boiling was not effective at the levels of metal bioaccumulation in hemolymph. It was observed that this metal bioaccumulation is more related with sex differences.
AtıfWoS2OpenAlex2İncele - MakaleAçık Erişim2013Scopus SJRQ4Determination of the Antioxidant Vitamin Levels in Fresh and Dried Bee Pollens in Bingol's Flora
Alayunt, Naci Omer; Karagözoglu, Yusuf; Parlak, Akif Evren; Türkoglu, Semra
In this study, fresh pollens collected from Bingol, province in Turkey were analyzed in June and the dried pollens stored by being kept in a cool, dark place for 8 months at room temperature were analyzed again in February. It was determined that, during this time, there was the maximum loss in the group Adakli with 68.23 % in terms of vitamin A, in the group Gokdere with 70.60 % in terms of vitamin E, in the group Adakli with 71.01 % in terms of vitamin C. These results obtained about the values of vitamin may vary depending on the geographic location where the pollen grows up, the season in which it is gathered and its drying and storage conditions.
AtıfWoS3OpenAlex4İncele - MakaleYalnız künye2013Scopus SJRQ2Relationship between fatigue and social support in hemodialysis patients
Karadag, Ezgi; Kilic, Serap Parlar; Metin, Ozgur
The aim of this study was to evaluate the relationship between fatigue and social support in hemodialysis patients in Turkey. This study was conducted on 73 patients receiving hemodialysis treatment in a hemodialysis unit in the province of Malatya between July and November 2011. A questionnaire consisting of 16 questions for sociodemographic and disease data was used together with the Multidimensional Scale of Perceived Social Support (MSPSS) and the Fatigue Severity Scale (FSS). In statistical evaluation, the Mann-Whitney U-test, independent t-test, Kruskal-Wallis test, and Pearson's correlation analysis were used. Correlation analysis between severity of fatigue in hemodialysis patients and social support revealed a significant relationship in the negative direction between fatigue severity and support from family (r=-0.404, P<0.05), support from friends (r=-0.635, P<0.05), support from a special person (r=-0.638, P<0.05) and overall support (r=-0.643, P<0.05). Patients with severe fatigue had low mean scores for support from family, friends, a special person and overall, whereas a high level of social support decreased the level of fatigue. When giving care to patients on hemodialysis, nurses should consider the effect of social support on fatigue and approach their patients from this perspective.
AtıfWoS27OpenAlex45İncele - MakaleYalnız künye2013Scopus SJRQ2THE EFFECTS OF HYDROXYUREA DERIVATIVE 1, 3, 4-THIADIAZOLES ON SERUM BIOCHEMICAL PARAMETERS AND ANTIOXIDANT STATUS IN LIVER OF RATS
Karagozoglu, Yusuf; Türkoglu, Semra; Parlak, Akif E.; Alayunt, Naci O.
In this study, it was aimed to investigate the antioxidant and antihepatotoxic effect of hydoxyurea derivative 1,3,4-thiadiazoles on serum biochemical parameters (AST, ALT, LDH, urea, creatinine and total bilirubin) and antioxidant parameters (SOD, CAT, GPX, MDA). In our study, a total of 35 adult male wistar rats were divided into 5 equal groups. DMSO diluted with only corn oil, was injected to the control group. 25 mg/kg ligand, 25 mg/kg thiadiazole-manganese, 25 mg/kg thiadiazole-cadmium and 25 mg/kg thiadiazole-chrome complexes was injected to the experimental groups rats subcutaneously for 15 days with three-day interval during the test. After blood samples were centrifuged AST, ALT, LDH enzyme activites hepatic injury; and then, the activites of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and the level of malondialdehyde (MDA) in liver tissues were determined spectrophotometrically. The level of AST was found to be lower (p<0.05) in the Cr-L group than in other groups. The levels of ALT and total bilirubine were found to be lower (p<0.05) in the Cd-L group than in other groups. The level of SOD was found to be higher (p<0.05) in the Cd-L group than in other groups. The levels of GPX was found to be lower (p<0.05) in the Cr-L group than in other groups. As a result, it can be concluded that their pharmacological characteristics can be beneficial in many fields of application because hydroxyurea derivative 1,3,4 thiadiazole compounds show the antioxidant and antihepatotoxic activity.
AtıfWoS1İncele - MakaleYalnız künye2013Scopus SJRQ3The Anesthetic Effects of Clove Oil and 2-Phenoxyethanol on Rainbow Trout (Oncorhynchus mykiss) at Different Concentrations and Temperatures
Yildiz, M.; Kayim, M.; Akin, S.
In this study, anesthetic effects of five different concentrations of 2-phenoxyethanol (0.2, 0.3, 0.4, 0.5 and 0.6 ml/L) and clove oil (0.50, 0.75, 1.00, 1.25 and 1.50 ml/L) on rainbow trout (Oncorhynchus mykiss) were studied at temperatures 7, 13 and 18 degrees C. For this purpose, 900 fish (39.08 +/- 1.13 g and 15.48 +/- 0.21 cm) were used in the experiment. Induction time of 2-phenoxyethanol and clove oil varied between 1.05 and 3.36 min at all concentrations, except for 0.2 ml/L (for 2-phenoxyethanol only) and at every temperature application. Full recovery time occurred between 2.44 and 7.14 min for 2-phenoxyethanol and 3.23 - 6.11 min for clove oil. It was found that full recovery times significantly increased with increase in 2-phenoxyethanol concentrations (r(2)=0.81). The same increasing trend was observed in clove oil, but the increase was not strong compared to 2-phenoxyethanol (r(2)=0.21). On the other hand, full induction times of 2-Phenoxyethanol and clove oil significantly declined with the increase in concentrations (r(2)=0.74; r(2)=0.84 for 2-phenoxyethanol and clove oil, respectively). Based on the ideal induction (less than 3 min) and recovery (less than 5 min) time criteria, it can be suggested that the most appropriate concentrations for rainbow trout were 0.3, 0.4 and 0.5 ml/L for 2-phenoxyethanol and 0.50, 0.75 and 1.00 ml/L for clove oil.
AtıfWoS16İncele - MakaleAçık Erişim2013Scopus SJRQ3Determination of phytochemical characteristics of the extract of Zea mays with Saccharomyces boulardii
Erecevit, Pinar; Kirbag, Sevda; Yilmaz, Okkes
Fatty acid, vitamin, phytosterol, flavonoid, and resveratrol contents and antimicrobial activities of Zea mays L. (corn) extracts treated with Saccharomyces boulardii were determined and compared. The total fatty acid, vitamin, and phytosterol contents in corn extract were at certain levels. It was detected that total fatty acid levels and vitamin contents of corn extracts prepared with Saccharomyces boulardii increased; however, flavonoid contents decreased at different rates. In addition to this, it was observed that naringin, resveratrol, and myricetin flavonoids were present in the extracts that contained S. boulardii. In the study, it was noticed that Z. mays L. (corn) had antioxidant and antimicrobial activities at different rates. It was observed that S. boulardii developing in extracts obtained from plants affected bioactive compounds at different rates.
AtıfWoS3OpenAlex4İncele - MakaleYalnız künye2013Scopus SJRQ2MULTI OBJECTIVE GENERALIZED RESOURCE CONSTRAINED TWO SIDED ASSEMBLY LINE BALANCING PROBLEM AND COMPUTATIONAL ANALAYSIS
Mete, Suleyman; Agpak, Kursad
Assembly of large size products like bus, truck and automobile can perform both sides of assembly line. In such cases, both sides (right and left) of the line are used to achieve for the assembly operation. These types of the lines are called as two sided assembly lines. When large size products are produced, sometimes they require a specific machine or a qualified staff to use this machine. This condition also exposes the problem of resource constraint. Therefore, in this study, a mathematical model for generalized resource constraint two sided assembly line balancing problem is presented, based on literature models and computational analysis is performed for multi-objective situation. Proposed model is run and analyzed over several known test problems by considering three objective functions (Minimization number of station, number of position and resource cost).
AtıfWoS8İncele - MakaleAçık Erişim2013Scopus SJRQ1Survival of Listeria monocytogenes during Production and Ripening of Traditional Turkish Savak Tulum Cheese and in Synthetic Gastric Fluid
Dikici, Abdullah; Calicioglu, Mehmet
This study investigated the survival and acid tolerance of Listeria monocytogenes during the 2-day processing stage and 90-day ripening of Savak tulum cheese, a traditional cheese in Turkey. Experimental Savak tulum cheese was produced from raw sheep's milk that was inoculated with a L. monocytogenes mixture consisting of five strains (average 7.0 log CFU/ml) and was ripened at 6 degrees C for 90 days. Microbiological and chemical analyses and acid exposure experiments in synthetic gastric fluid (SGF) (pH 1.5 to 2.5) were carried out on days 1 and 2 during processing and on days 0, 15, 30, 45, 60, and 90 during ripening. The numbers of L. monocytogenes did not decrease during processing, but a total of 4.1 log CFU/g reduction was observed during ripening. Throughout the ripening period, L. monocytogenes cells survived direct 90-min exposures of the cheese samples to SGF. These results suggest that, although the pathogen numbers decreased in Savak tulum cheese ripened at 6 degrees C for 90 days, a sublethal environment may have occurred in the cheese during the production stage, activating the acid-tolerance mechanisms of the pathogen and allowing L. monocytogenes to maintain its viability in the SGF for 90 min.
AtıfWoS4OpenAlex6İncele - MakaleYalnız künye2013Scopus SJRQ2Micelle nano-reactors as mediators of water-insoluble ligand complexation with Cu(II) ions in aqueous medium
Adigüzel, Ragip; Tascioglu, Senay
Complexation reactions between water-soluble and -insoluble reactants were shown to occur in aqueous media in the presence of normal or reverse surfactant micelles, in significantly higher yields at lower temperatures compared to those achieved in neat organic solvents. The highest yield enhancement in the complexation of novel water-insoluble bis(2-amino-1,3,4-thiadiazolyl)methane and 1,4-bis(2-amino-1,3,4-thiadiazolyl)benzene ligands with Cu(II) ions was achieved in the sodium bis(2-ethylhexyl)sulfosuccinate (AOT)-heptane-water reverse micellar system at the hydration ratio of 15. The results revealed that AOT normal micelles cause a change in the reaction mechanism together with the enhancement of the complex formation. The observed micellar effects were rationalized on basis of the properties of bulk solvents, surfactants and ligands, considering the solvation and hydration ratios of reverse micelles. The results have proved the dependence of complex yield on the amount and accordingly also on the properties of water in the micellar core, indicating that the yield can be maximized by the optimization of the hydration ratio.
AtıfWoS4OpenAlex5İncele - MakaleYalnız künye2013Scopus SJRQ1Extrusion Cooking of Lentil Flour (Lens Culinaris-Red)-Corn Starch-Corn Oil Mixtures
Dogan, H.; Gueven, A.; Hicsasmaz, Z.
An expanded food product was obtained from lentil flourcorn starchcorn oil mixtures by extrusion cooking. Effects of protein, lipid, and moisture contents of the feed mixture; cooking temperature and screw speed on starch gelatinization; protein insolubility; and lipid complexation were investigated. Effects of these functional properties on expansion ratio, cell size distribution, and cutting strength were assessed. Optimum feed composition was 67% lentil flour, 30% corn starch, and 3% corn oil (db). This mixture was processed at 15% moisture content and 178 degrees C temperature. Expansion ratio was 3.7 and degree of gelatinization was 0.70.
AtıfWoS20OpenAlex29İncele - MakaleAçık Erişim2013Scopus SJRQ2Self-dual metrics on non-simply connected 4-manifolds
Kalafat, Mustafa; Ozan, Yildiray; Arguez, Hulya
We construct self-dual (SD) but not locally conformally flat (LCF) metrics on families of non-simply connected 4-manifolds with small signature. We construct various sequences with bounded or unbounded Betti numbers and Euler characteristic. These metrics have negative scalar curvature. As an application, this is used to address Remark 4.79 of [1]. (C) 2012 Elsevier B.V. All rights reserved.
AtıfWoS3OpenAlex6İncele - MakaleYalnız künye2013Scopus SJRQ3Elimination of Radiation Damping Effects from the NMR Relaxation Curves of H2O/D2O Mixtures Containing Protein and Ions
Zengin, Bilgin; Koylu, Mehmet Zafer; Korunur, Sibel; Yilmaz, Ali
In this work the T-1 and T-2 curves of H2O/D2O mixtures were obtained for several fractions of H2O and also for different amounts of albumin and manganese. The experiments were carried out with a 400 MHz proton NMR spectrometer. The T-1 and the T-2 curves were determined by the inversion recovery (IR) and Carr-Purcell-Meiboom-Gill (CPMG) sequences, respectively. The relaxation times in residual water and in a mixture with 0.05 ml H2O were found to be reliable either in the presence or in the absence of albumin. The mixtures containing 0.1 ml or higher H2O suffer from radiation damping (RD). RD was removed gradually by addition of albumin or manganese. RD in the protein solution with 0.1 ml H2O was removed by adding 1 mu g of manganese to one ml of solution. The data suggest that the relaxation times in H2O/D2O mixtures are measurable by conventional methods upon the addition of appropriate amounts of manganese and albumin.
AtıfWoS2İncele - MakaleAçık Erişim2013Scopus SJRQ3Mechanical and thermal properties of polyamide versus reinforced PMMA denture base materials
Soygun, Koray; Bolayir, Giray; Boztug, Ali
PURPOSE. This in vitro study intended to investigate the mechanical and thermal characteristics of Valplast, and of polymethyl methacrylate denture base resin in which different esthetic fibers (E-glass, nylon 6 or nylon 6.6) were added. MATERIALS AND METHODS. Five groups were formed: control (PMMA), PMMA-E glass, PMMA-nylon 6, PMMA-nylon 6.6 and Valplast resin. For the transverse strength test the specimens were prepared in accordance with ANSI/ADA specification No.12, and for the impact test ASTM D-256 standard were used. With the intent to evaluate the properties of transverse strength, the three-point bending (n=7) test instrument (Lloyd NK5, Lloyd Instruments Ltd, Fareham Hampshire, UK) was used at 5 mm/min. A Dynatup 9250 HV (Instron, UK) device was employed for the impact strength (n=7). All of the resin samples were tested by using thermo-mechanical analysis (Shimadzu TMA 50, Shimadzu, Japan). The data were analyzed by Kruskal-Wallis and Tukey tests for pairwise comparisons of the groups at the 0.05 level of significance. RESULTS. In all mechanical tests, the highest values were observed in Valplast group (transverse strength: 117.22 +/- 37.80 MPa, maximum deflection: 27.55 +/- 1.48 mm, impact strength: 0.76 +/- 0.03 kN). Upon examining the thermo-mechanical analysis data, it was seen that the E value of the control sample was 8.08 MPa, higher than that of the all other samples. CONCLUSION. Although Valplast denture material has good mechanical strength, its elastic modulus is not high enough to meet the standard of PMMA materials.
AtıfWoS67OpenAlex110İncele