Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Uzun, Sevda(64)
- Merdan, Mehmet(47)
- Baltaci, Cemalettin(35)
- Kulakaç, Nurşen(28)
- Duran, Celal(27)
- Ozdes, Duygu(24)
- Turan, Ibrahim(24)
- Demir, Selim(23)
- Türkkan, Tuğba(22)
- Bayrakdaroglu, Serdar(21)
- Topal, Fevzi(21)
- Öztürk, Serkan(21)
- Ürkek, Bayram(21)
- Gücer, Mehmet Ali(20)
- Akar, Zeynep(19)
- Kaygusuz, Abdullah(19)
- Topal, Meryem(19)
- Anaç, Halil(18)
- Aydin, Aydanur(18)
- Batan, Nevzat(18)
- Erata, Hüseyin(18)
- Tuncer, Metin(18)
- Akyürek, Suat(17)
- Baltacı, Cemalettin(17)
- Karimullah, Suud Sarim(17)
- Acet, Tuba(16)
- Akar, Bülent(16)
- Ashyralyyev, Charyyar(16)
- Düzgün, Azer Özad(16)
- Hintistan, Sevilay(16)
- Yılmaz, Coşkun(16)
- Aliyazicioglu, Yuksel(15)
- Kaya, Hacer(15)
- Kurnaz, Muammer(15)
- Kurt, Kemal(15)
- Ozden, Talat(15)
- Yilmaz, Coskun(15)
- Yuksel, Ferhat(15)
- Yücel, Cem(15)
- Öz, Mehmet(15)
Yayınlar
- MakaleAçık Erişim2016Scopus SJRQ4On the fractional Riccati differential equation
Khaniyev, Tahir; Merdan, Mehmet
In this paper, We tried to find an analytical solution of nonlinear Riccati conformable fractional differential equation. Fractional derivatives are described in the conformable derivative. The behavior of the solutions and the effects of different values of fractional order α are presented graphically and table. The results obtained by the CFD(conformable fractional derivative) are compared with homotopy perturbation method(HPM), fractional variational iteration method(FVIM).
AtıfScopus3OpenAlex3
İncele - BildiriAçık Erişim2016The impossibility of producing I-131 from its daughter Xe-131 by photonuclear reactions
Bayram, Tuncay; Akkoyun, Serkan; Çelik, Necati; Haciislamoǧlu, Emel; Uruk, Serhat; Şentürk, Şevki; Ristic, G
131I is one of the radioisotopes in nuclear medicine procedures for diagnostic and treatment purposes. It decays to 131Xe by emitting beta particles. In this study, we have investigated the reproduction possibility of 131I from 131Xe by using different reactions, including a photonuclear reaction step. We have used TALYS computer program for calculating cross-sections of the reactions. It was seen that it was not an easy task to reproduce 131I from its decay product 131Xe because of low reaction cross-section values. According to the results, we have seen that the calculations are in harmony with the TENDL 2014 database.
- MakaleAçık Erişim2016Scopus SJRQ3Additional operation learning process to the mild intellectual disabilities students by means of virtual manipulatives: A multiple case study
Öztürk, Mesut; Akkan, Yaşar; Büyüksevindik, Baki; Kaplan, Abdullah
It is frequently emphasized that technology integration to the education of the students have intellectual disabilities has great importance. The researches performed show that using virtual manipulatives consist positive effects on learning mathematics on the students have intellectual disabilities. This study was done to investigate the addition operation learning process of the students have intellectual disabilities. Two students have mild intellectual disabilities and are 14 and 17 years old participated to this research conducted by means of multiple case study is one of the qualitative research designs. In this study was realized during five schedules data were collected through interviews, observations and documents. Content analysis were used for data analysis. At the end of the analysis, three categories of findings on "Learning of the addition operation", "Opinions on the use of computer and virtual manipulatives" and "Individual differences", were structured.
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İncele - MakaleAçık Erişim2016Scopus SJRQ29,10-Dibromo-N-aryl-9,10-dihydro-9,10-[3,4]epipyrroloanthracene-12,14-diones: Synthesis and Investigation of Their Effects on Carbonic Anhydrase Isozymes I, II, IX, and XII
Göksu, Haydar; Topal, Meryem; Keskin, Ali; Gültekin, Mehmet S.; Çelik, Murat; Gülçin, Ilhami; Tanc, Muhammet; Supuran, Claudiu T.
N-substituted maleimides were synthesized from maleic anhydride and primary amines. 1,4-Dibromo-dibenzo[e,h]bicyclo-[2,2,2]octane-2,3-dicarboximide derivatives (4a-f) were prepared by the [4+2] cycloaddition reaction of dibromoanthracenes with the N-substituted maleimide derivatives. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory effects of the new derivatives were assayed against the human (h) isozymes hCA I, II, IX, and XII. All tested bicyclo dicarboximide derivatives exhibited excellent inhibitory effects in the nanomolar range, with Ki values in the range of 117.73-232.87 nM against hCA I and of 69.74-111.51 nM against hCA II, whereas they were low micromolar inhibitors against hCA IX and XII. A series of 9,10-dibromo-N-aryl-9,10-dihydro-9,10-[3,4]epipyrroloanthracene-12,14-diones (4a-f) were synthesized from N-substituted maleimide derivatives and 9,10-dibromoanthracene. Compounds 4a-f were assayed against human carbonic anhydrases (hCA) IX and XII, which are the two tumor-associated isozymes, and hCA I and II, which represent the most common off-targets for the development of selective anticancer CA inhibitors.
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İncele - MakaleAçık Erişim2016Scopus SJRQ2Assessing the effects of long-term recreational activities on landscape changes in Abant Natural Park, Turkey
Çakir, Günay; Müderrisoğlu, Haldun; Kaya, Latif Gürkan
Natural, protected areas offer many possibilities for recreation in rural areas such as camping, one of the most popular activities. The system established for protected areas in Turkey aims to provide a foundation for conserving areas for recreation. One such area, Abant Natural Park, is convenient for visits from Turkey’s two most populated metropolitan areas, Istanbul and Ankara. It also attracts tourists from other regions and countries. The aim of the present study was to evaluate the vegetation loss and land cover changes due to picnic/camping, transhumance, and construction over 40 years (1966–2004) in the park using data on visitor numbers, vegetation patches, corridors and connectivity. For evaluating landscape variables, remote sensing data and aerial photos were used. When aerial photos were imported into the ERDAS Imagine program, ground control points identified, and individual images orthorectified, land degradation was not found in the use of camping areas. Moreover, manmade areas (road, car park and hotel) observably increased, thus decreasing the forest lands. The findings show that the land use types that have had the greatest ecological impact are transhumance and construction of hotels, which also require infrastructure development. The intensity of the ecological effects mandates precautions to lessen the impacts and the need for continuing assessment to ensure sustainable use of the area.
AtıfScopus19WoS16OpenAlex19İncele - MakaleAçık Erişim2016Scopus SJRQ1Effect of piracetam and nimodipine on full-thickness skin burns in rabbits
Sari, Elif; Dincel, Gungor C.
The potential of several drugs for full-thickness skin burns has been investigated, but the treatment of such burns remains a challenge in plastic surgery. The present study was designed to determine the effect of systemic and topical administration of piracetam and nimodipine on full-thickness skin burn wound healing. A total of 36 New Zealand male rabbits were divided into six groups. Full-thickness skin burns were produced in all the groups, except the control group. Piracetam was administered systemically (piracetam-IV) and topically (piracetam-C) for 14 days, and nimodipine was administered systemically (nimodipine-IV) and topically (nimodipine-C) over the burn wounds for 14 days. The sham group underwent burn injury but was not administered any drug. After 21 days, gross examination and histopathological analysis were performed and the results were compared statistically. Nimodipine-C and nimodipine-IV had no effect on burn wound healing. However, both piracetam-IV and piracetam-C significantly enhanced the healing of the full-thickness skin burn wounds, although the latter was more effective, useful and practical in burn wound healing. The histopathological features of the wounds in the piracetam-C group were closer to those of the control group than those of the other groups. Piracetam-C rather than piracetam-IV may promote full-thickness burn wound healing in rabbits.
AtıfScopus2WoS2OpenAlex2İncele - MakaleAçık Erişim2016Scopus SJRQ3Separation and preconcentration of Pb(II) and Cu(II) ions via carrier element-free coprecipitation using an acetohydrazide derivative
Tümay, Süreyya Oǧuz; Yazar, Murat; Ozdeş, Duygü; Bektaş, Hakan; Duran, Celal
A new method based on the combination of carrier element-free coprecipitation and flame atomic absorption spectrometric determination has been investigated for simultaneous separation and preconcentration of Pb(II) and Cu(II) ions in some environmental solid and liquid samples. The 2-f3-(4-methylbenzyl)-4-[2-(1H-indol-3-yl)ethyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-ylg -N'-(phenylmethylene) acetohydrazide (MITA) was utilized as an organic coprecipitating agent without using a carrier element for coprecipitation of the analyte ions. The effects of experimental conditions including aqueous solution pH, MITA quantity, sample volume, standing time, and centrifugation rate and time were investigated in detail and optimized. The influences of some foreign ions were also evaluated on the quantitative recoveries of the analyte ions. The preconcentration factors were 125 for both analyte ions. The detection limits were 1.32 μgL-1 and 0.47 μg L-1 for Pb(II) and Cu(II) ions, respectively, and the relative standard deviations (RSDs) were lower than 4% for both analyte ions. After the accuracy of the method was checked, it was applied to sea and stream water as liquid samples and waste tea and tobacco as solid samples to determine the levels of Pb(II) and Cu(II) ions.
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İncele - MakaleAçık Erişim2016Scopus SJRQ1Geochronology and geochemistry of Eocene-aged volcanic rocks around the Bafra (Samsun, N Turkey) area: Constraints for the interaction of lithospheric mantle and crustal melts
Temizel, Irfan; Arslan, Mehmet; Yücel, Cem; Abdioğlu, Emel; Ruffet, Gilles
40Ar-39Ar age, whole-rock chemical, and Sr-Nd isotope data are presented for the post-collisional, Eocene (51.3-44.1 Ma)-aged volcanic rocks from the Bafra (Samsun) area in the western part of the Eastern Pontides (N Turkey) aiming to unravel their sources and evolutionary history. The studied Eocene volcanic rocks can be divided into two groups: analcime-bearing (tephritic lava flows and dykes) and analcime-free (basaltic to trachytic lava flows and basaltic dykes). The analcime-bearing volcanic rocks have a fine-grained porphyritic texture with clinopyroxene phenocrysts, whereas analcime-free volcanic rocks show a variety of textures including hyalo-microlitic microgranular porphyritic, intersertal, trachytic, fluidal, and glomeroporphyritic. The volcanic rocks also show evidence of mineral-melt disequilibrium textures such as sieved, rounded, and corroded plagioclases, partially melted and dissolved clinopyroxenes and poikilitic texture. Petrochemically, the parental magmas of the volcanic rocks evolved from alkaline to calc-alkaline lava suites and include high-K and shoshonitic compositions. They display enrichments in light rare earth and large ion lithophile elements such as Sr, K, and Rb, as well as depletions in high field strength elements such as Nb, Ta, Zr, and Ti, resembling subduction-related magmas. The analcime-bearing and -free volcanic rocks share similar incompatible element ratios and chondrite-normalised rare rearth element patterns, indicating that they originated from similar sources. They also have relatively low to moderate initial 87Sr/86Sr (0.7042-0.7051), high positive εNd(t) values (+0.20 to +3.32), and depleted mantle Nd model ages (TDM1 = 0.63-0.93 Ga, TDM2 = 0.58-0.84 Ga). The bulk-rock chemical and Sr-Nd isotope features as well as the high Rb/Y and Th/Zr, but low Nb/Zr and Nb/Y ratios, indicate that the volcanic rocks were derived from a lithospheric mantle source that had been metasomatised by slab-derived fluids. Trace element modelling suggests that the parental magma(s) of the volcanic rocks represent mixtures of melts derived by low-degree (~5-10%) partial melting of spinel-lherzolite (40-85%) and garnet-lherzolite (15-60%) mantle sources. Sr-Nd isotopic modelling also suggests that a 25-35% lower crustal component was added in the parental magmas; AFC modelling additionally indicates minor upper crustal contamination during the evolution of the volcanic rocks. In conclusion, integration of the geochemical, petrologic, and isotopic data with regional geology suggests that the analcime-bearing and -free volcanic rocks evolved from parental magma(s) derived from melts of a subcontinental lithospheric mantle and lower crustal sources.
AtıfScopus44WoS43OpenAlex49İncele - MakaleAçık Erişim2016Scopus SJRQ2Synthesis of new 1,2,4-triazole compounds containing Schiff and Mannich bases (morpholine) with antioxidant and antimicrobial activities
Ünver, Yasemin; Deniz, Sadik; Çelik, Fatih; Akar, Zeynep; Küçük, Murat; Sancak, Kemal
Compound 2 was synthesized by reacting CS2/KOH with compound 1. The treatment of compound 2 with hydrazine hydrate produced compound 3. Then, compound 3 was converted to Schiff bases (4a–d) by the handling with several aromatic aldehydes. The treatment of triazole compounds 4a–d containing Schiff base with morpholine gave compounds 5a–d. All compounds were tested for their antioxidant and antimicrobial activities. The antioxidant test results of DPPH• radical scavenging and ferric reducing/antioxidant power methods showed good antioxidant activity. The triazole-thiol (3) was the most active, and the effect of the substituent type of the thiophene ring on the activity was same for both Schiff bases (4a–d) and Mannich bases (5a–d). Among the newly synthesized triazole derivatives, the Schiff base 4d and the Mannich base 5d carrying nitro substituent on the thiophene ring showed promising antibacterial and antifungal activity, with lower MIC values than the standard antibacterial ampicillin.
AtıfScopus99WoS94OpenAlex104İncele - MakaleAçık Erişim2016Scopus SJRQ3Effect of apple fibre on textural and relaxation properties of wheat chips dough
Karaman, S.; Yilmaz, M.T.; Toker, O.S.; Yuksel, F.; Kayacier, A.; Dogan, M.
In this study, the effect of apple fibre with different levels of fibres (5, 10, 15 and 20%) was investigated on viscoelastic nature and the textural properties of wheat chips dough using stress relaxation test and texture profile analysis. Apple fibre addition changed the stress relaxation properties of wheat dough, depending on fibre concentration. Increase in the fibre concentration increased resistance of the dough samples to the deformation by increasing their elasticity. Hardness and gumminess values increased while springiness, cohesiveness and resilience values decreased as apple fibre level increased. Significant correlations were found between stress relaxation and texture profile analysis parameters. In order to describe the effect of apple fibre on the viscoelastic properties of wheat dough, generalised Maxwell, Nussinovitch and Peleg models were fitted to experimental stress relaxation data. All three models were found to be efficient in describing the stress-relaxation behaviour of wheat dough; but, the Maxwell model was the most effective. In addition, power-law and exponential functions were successfully used to describe the effect of apple fibre concentration on the constants related with stress relaxation data and textural parameters.
AtıfScopus3WoS3OpenAlex3İncele - MakaleAçık Erişim2016Scopus SJRQ2Investigation of Hydroxymethylfurfural Formation in Herle
Baltacı, Cemalettin; Ilyasoglu, Huri; Gundogdu, Ali; Ucuncu, Osman
Mulberry pestil and köme are Turkish traditional foods made from herle. Browning leads to quality losses in the herle, and its products. In this study, the effect of thermal treatment on the hydroxymethylfurfural formation and color values in the herle was evaluated. The herle samples were kept at different temperatures (60–110°C) and times (2–6 h). The hydroxymethylfurfural formation was found to increase with increasing time and temperature. The legal limit for hydroxymethylfurfural in the pestil (50 mg/kg) was exceeded at temperatures above 90°C. The lightness (L* value) of the sample decreased with the thermal treatment, indicating browning.
AtıfScopus10WoS10OpenAlex12İncele - MakaleAçık Erişim2016Scopus SJRQ3Mediostoma izmirica sp. nov.: A new harvestman species (Arachnida, Opiliones, Nemastomatidae) from Turkey
Snegovaya, Nataly Yu.; Kurt, Kemal; Yağmur, Ersen A.
A new harvestman species of the genus Mediostoma Kratochvil, 1958, Mediostoma izmirica sp. nov., is described and illustrated based on males and females from İzmir Province, Turkey. Differences between the new species and other species of the genus Mediostoma are indicated. Scanning electron microscope photographs of its characteristic structures are also given.
AtıfScopus3WoS2OpenAlex2İncele - MakaleAçık Erişim2016Scopus SJRQ1Utilization of stale bread in fried wheat chips: Response surface methodology study for the characterization of textural, morphologic, sensory, some physicochemical and chemical properties of wheat chips
Yuksel, Ferhat; Kayacier, Ahmed
Wheat chips enriched with stale bread were produced and response surface methodology was used for the studying the simultaneous effects of stale bread level (0-50 g/100g), frying temperature (170-190 °C) and frying time (40-60 s) on some physicochemical, chemical, textural, morphological and sensorial properties of chips. Additionally, product optimization was performed by using ridge analysis to detect the optimum levels of process variables. The dry matter, ash, Hunter Lab a and b values of samples increased with the increasing stale bread level. Higher frying temperature caused a decrease in the hardness and water activity values. Also, addition of stale bread in the formulation of chips decreased the oil uptake of samples significantly (p < 0.01). Sensory values of wheat chips increased with the increasing stale bread level. In general, panelists preferred wheat chips enriched with stale bread compared to control sample. The addition of stale bread made the structure of chips firm and electron microscopy analysis revealed that pores and fractures of chips decreased for the samples containing stale bread, which resulted in lower oil uptake during frying.
AtıfScopus24WoS18İncele - MakaleAçık Erişim2016Scopus SJRQ4Comparison of immunoglobulin (IgG, IgM) concentrations in calves raised under organic and conventional conditions
Bayram, Bahri; Aksakal, Vecihi; Turan, Ibrahim; Demir, Selim; Mazlum, Halit; Çosar, Ikram
The objective of study was conducted on to compare immunoglobulin (Ig) concentrations in calves raised under organic and conventional conditions. 30 newborn Holstein Friesian calves (15 rose under organic and 15 under conventional conditions) in two dairy cattle farms. Blood samples were taken from 30 newborn calves at birth (before taking colostrum) and on 14th day to compare immunoglobulin (Ig) concentrations in calves raised under organic and conventional conditions. Furthermore, blood and colostrum samples were also taken from the mothers included into the study. IgG and IgM concentrations in colostrum and blood serums were determined using commercial ELISA kits. IgG concentrations at birth (0.79±0.34, 1.64±0.95 mg/mL) and on the 14th day (46.5±21.5, 70.5±27.8 mg/mL) in calves raised under organic conditions were lower than those raised under conventional conditions (p<0.01). Calves raised under organic conditions also had lower IgM concentrations than calves raised under conventional conditions at birth (0.23±0.03 and 0.28±0.11 mg/mL, respectively) and on the 14th day (2.76±0.56 and 4,30±1.03 mg/mL, respectively) (p<0.05, p<0.01). IgG concentrations in the blood serum of cows raised under conventional conditions were higher than those raised under organic conditions (p<0.01), while no difference was found with respect to IgM concentrations (p>0.05). No difference was found in the IgG and IgM concentrations of colostrum obtained from cows raised under organic and conventional conditions. In both the husbandry systems, positive and significant (p<0.01) correlations were found between the Ig concentrations of the mothers and offsprings. Consequently, it can be suggested that higher Ig concentrations in cattle raised under conventional conditions might be due to poorer environmental conditions.
AtıfScopus5WoS4OpenAlex9İncele - MakaleAçık Erişim2016Scopus SJRQ2Antioxidant activity of taxifolin: An activity-structure relationship
Topal, Fevzi; Nar, Meryem; Gocer, Hulya; Kalin, Pinar; Kocyigit, Umit M.; Gülçin, Ilhami; Alwasel, Saleh H.
Taxifolin is a kind of flavanonol, whose biological ability. The objectives of this study were to investigate the antioxidants and antiradical activities of taxifolin by using different in vitro bioanalytical antioxidant methods including DMPD•+, ABTS•+, and DPPH•-scavenging effects, the total antioxidant influence, reducing capabilities, and Fe2+-chelating activities. Taxifolin demonstrated 81.02% inhibition of linoleic acid emulsion peroxidation at 30 μg/mL concentration. At the same concentration, standard antioxidants including trolox, α-tocopherol, BHT, and BHA exhibited inhibitions of linoleic acid emulsion as 88.57, 73.88, 94.29, and 90.12%, respectively. Also, taxifolin exhibited effective DMPD•+, ABTS•+, and DPPH•-scavenging effects, reducing capabilities, and Fe2+-chelating effects. The results obtained from this study clearly showed that taxifolin had marked antioxidant, reducing ability, radical scavenging and metal-chelating activities. Also, this study exhibits a scientific shore for the significant antioxidant activity of taxifolin and its structure-activity insight.
AtıfScopus290WoS255OpenAlex306İncele - MakaleAçık Erişim2016Scopus SJRQ1Subduction-related Late Cretaceous high-K volcanism in the Central Pontides orogenic belt: constraints on geodynamic implications
Aydınçakır, Emre
Mineral chemistry, major and trace elements, 40Ar/39Ar age and Sr–Nd–Pb isotopic data are presented for the Late Cretaceous Hamsilos volcanic rocks in the Central Pontides, Turkey. The Hamsilos volcanic rocks mainly consist of basalt, andesite and associated pyroclastics (volcanic breccia, vitric tuff and crystal tuff). They display shoshonitic and high-K calc-alkaline affinities. The shoshonitic rocks contain plagioclase, clinopyroxene, alkali feldspar, phlogopite, analcime, sanidine, olivine, apatite and titanomagnetite, whereas the high-K calc-alkaline rocks contain plagioclase, clinopyroxene, orthopyroxene, magnetite / titanomagnetite in microgranular porphyritic, hyalo-microlitic porphyritic and glomeroporphyritic matrix. Mineral chemistry data reveal that the pressure condition of the clinopyroxene crystallisation for the shoshonitic rocks are between 1.4 and 6.3 kbar corresponds to 6–18-km depth and the high-K calc-alkaline rocks are between 5 and 12 km. 40Ar/39Ar age data changing between 72 ± .5 Ma and 79.0 ± .3 Ma (Campanian) were determined for the Late Cretaceous Hamsilos volcanic rocks, contemporaneous with the subduction of the Neo-Tethyan Ocean beneath the Pontides. The studied volcanic rocks were enriched in the large-ion lithophile and light rare earth element contents, with pronounced depletion in the contents of high-field-strength elements. Chondrite-normalised rare earth element patterns (LaN/LuN = 6–17) show low to medium enrichment, indicating similar sources of the rock suite. Initial 87Sr/86Sr values vary between.70615 and.70796, whereas initial 143Nd/144Nd values change between.51228 and.51249. Initial 206Pb/204Pb values vary between 18.001 and 18.349, 207Pb/204Pb values between 15.611 and 15.629 and 208Pb/204Pb values between 37.839 and 38.427. The main solidification processes involved in the evolution of the volcanic rocks consist of fractional crystallisation, with minor amounts of crustal contamination ± magma mixing. According to geochemical evidence, the shoshonitic melts in the Hamsilos volcanic rocks were possibly derived from the low degree of partial melting of a subcontinental lithospheric mantle (SCLM), while the high-K calc-alkaline melts were derived from relatively high degree of partial melting of SCLM that was enriched by fluids and/or sediments from a subduction of oceanic crust.
AtıfScopus26WoS20OpenAlex27İncele - MakaleAçık Erişim2016Scopus SJRQ2Determination of biological performance, dimensional stability, mechanical and thermal properties of wood-plastic composites produced from recycled chromated copper arsenate-treated wood
Tascioglu, Cihat; Tufan, Mursit; Yalcin, Mesut; Sen, Selim
The aim of this study was to investigate the dimensional stability, mechanical and biological performance and thermal degradation of wood-plastic composites made from high-density polyethylene and recycled wood treated with chromated copper arsenate (CCA), a commonly used wood preservative chemical. Virgin pine wood samples were also prepared with and without a coupling agent and used as the control group. Samples of CCA-treated Scots pine (Pinus sylvestris L.) with varying wood content were produced by adding different ratios of the coupling agent. The recycled CCA-treated wood-filled composites exhibited better flexural and tensile strength properties and dimensional stability than the control group, whilst their impact strength was less. Biological test values showed improved durability against termites and fungus with the recycled CCA-treated wood-filled composites. In addition, the leaching of heavy metals was significantly diminished when the coupling agent was utilized at a level of 5% (w/w), thus presenting a much lower impact on the environment.
AtıfScopus21WoS21OpenAlex20İncele - MakaleAçık Erişim2016Scopus SJRQ2Use of polyvinyl chloride (PVC) powder and granules as aggregate replacement in concrete mixtures
Bolat, Hakan; Erkus, Pinar
Concrete is one of the materials in which polymer wastes are utilized. Generally, these wastes are added at specific rates in scientific studies but an important problem of waste polymers is size irregularity. Even when consistent dosage rates are used, variations in polymer size can lead to variability in the physical and mechanical properties of the concrete produced. The aim of this study is to determine physical and mechanical properties of polyvinyl chloride (PVC)-containing concretes. In order to produce normal and high strength concretes, 10%, 20%, and 30% replacement ratios of PVC powder and granules by volume of aggregate are used. Slump, fresh and hardened densities, compressive strength, capillary water absorption, and abrasion were tested on all concrete types. As the PVC ratio increases, important changes are seen in all physical and mechanical concrete properties. The unit weights of the 10%, 20%, and 30% replacement PVC powder concretes are lower by ∼4%, 8%, and 13%, respectively, as compared to the reference mixtures, and the replacement PVC granule concretes are lower by ∼2%, 4%, and 7%. Compressive strength test results showed similar trends. As PVC replacement increases, the capillary water absorption decreases between 10% and 50%, and abrasion decreases between 27% and 77%.
AtıfScopus41WoS33OpenAlex48İncele - MakaleAçık Erişim2016Scopus SJRQ2Antioxidant, antiradical, and anticholinergic properties of cynarin purified from the Illyrian thistle (Onopordum illyricum L.)
Topal, Meryem; Gocer, Hulya; Topal, Fevzi; Kalin, Pinar; Köse, Leyla Polat; Gulçin, Ilhami; Çakmak, Kader C.; Küçük, Murat; Durmaz, Lokman; Gören, Ahmet C.
Cynarin is a derivative of hydroxycinnamic acid and it has biologically active functional groups constituent of some plants and food. We elucidated the antioxidant activity of cynarin by using different in vitro condition bioanalytical antioxidant assays like DMPD•+, ABTS•+, DPPH• and H2O2 scavenging effects, the total antioxidant influence, reducing capabilities, Fe2+ chelating and anticholinergic activities. Cynarin demonstrated 87.72% inhibition of linoleic acid lipid peroxidation at 30 g/mL concentration. Conversely, some standard antioxidants like trolox, tocopherol, butylated hydroxytoluene (BHT), and butylated hydroxyanisole (BHA) exhibited inhibitions of 90.32, 75.26, 97.61, 87.30%, and opponent peroxidation of linoleic acid emulsion at the identical concentration, seriatim. Also, cynarin exhibited effective DMPD•+, ABTS•+, DPPH•, and H2O2 scavenging effects, reducing capabilities and Fe2+ chelating effects. On the contrary, IC50 and Ki parameters of cynarin for acetylcholinesterase enzyme inhibition were determined as 243.67 nM (r2: 0.9444) and 39.34 ± 13.88 nM, respectively. This study clearly showed that cynarin had marked antioxidant, anticholinergic, reducing ability, radical-scavenging, and metal-binding activities.
AtıfScopus169WoS156OpenAlex169İncele - MakaleAçık Erişim2016Scopus SJRQ1Comparison of verona integron-borne metallo-β-lactamase (VIM) variants reveals differences in stability and inhibition profiles
Makena, Anne; Düzgün, Azer Ö.; Brem, Jürgen; McDonough, Michael A.; Rydzik, Anna M.; Abboud, Martine I.; Saral, Ayşegül; Çiçek, Ayşegül Č.; Sandalli, Cemal; Schofield, Christopher J.
Metallo-β-lactamases (MBLs) are of increasing clinical significance; the development of clinically useful MBL inhibitors is challenged by the rapid evolution of variant MBLs. The Verona integron-borne metallo-β-lactamase (VIM) enzymes are among the most widely distributed MBLs, with>40 VIM variants having been reported. We report on the crystallographic analysis of VIM-5 and comparison of biochemical and biophysical properties of VIM-1, VIM-2, VIM-4, VIM-5, and VIM-38. Recombinant VIM variants were produced and purified, and their secondary structure and thermal stabilities were investigated by circular dichroism analyses. Steady-state kinetic analyses with a representative panel of β-lactam substrates were carried out to compare the catalytic efficiencies of the VIM variants. Furthermore, a set of metalloenzyme inhibitors were screened to compare their effects on the different VIM variants. The results reveal only small variations in the kinetic parameters of the VIM variants but substantial differences in their thermal stabilities and inhibition profiles. Overall, these results support the proposal that protein stability may be a factor in MBL evolution and highlight the importance of screening MBL variants during inhibitor development programs.
AtıfScopus45WoS42İncele