Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Uzun, Sevda(87)
- Merdan, Mehmet(70)
- Duran, Celal(56)
- Baltaci, Cemalettin(52)
- Kulakaç, Nurşen(51)
- Ozdes, Duygu(51)
- Kaygusuz, Abdullah(47)
- Öztürk, Serkan(42)
- Demir, Selim(40)
- Karsli, Orhan(37)
- Turan, Ibrahim(37)
- Dokuz, Abdurrahman(36)
- Gücer, Mehmet Ali(36)
- Sipahi, Ferkan(36)
- Araz, Onur(35)
- Kandemir, Raif(31)
- Vural, Alaaddin(31)
- Topal, Fevzi(30)
- Kurt, Kemal(29)
- Ürkek, Bayram(29)
- Maden, Nafiz(28)
- Acet, Tuba(27)
- Alemdag, Selcuk(26)
- Arslan, Mehmet(26)
- Ayaydin, Hasan(26)
- Akaryali, Enver(25)
- Aydin, Faruk(25)
- Baltacı, Cemalettin(25)
- Yücel, Cem(25)
- Akar, Zeynep(24)
- Barut, Abdulkadir(24)
- Ozturk, Samet(24)
- Pala, Fahrettin(24)
- Peker, Iskender(24)
- Topal, Meryem(24)
- Yildiz, Salih(24)
- Öz, Mehmet(24)
- Aliyazicioglu, Yuksel(23)
- Bostan, Sedat(23)
- Kankal, Murat(23)
Yayınlar
- MakaleYalnız künye2014Scopus SJRQ1Microstructural, mechanical and tribological properties of Al-7Si-(0-5)Zn alloys
Alemdaǧ, Yasin; Beder, Murat
A series of Al-7Si-(0-5)Zn alloys were produced by permanent mould casting and their microstructure, mechanical and tribological properties were investigated in as-cast state. The microstructure of Al-7Si alloy consisted of α-Al dendrites surrounded by eutectic Al-Si mixture and a small amount of primary silicon particles. Addition of zinc into Al-7Si alloy resulted in the formation of α-solid solution and an increase in size and volume fraction of primary silicon particles. Moreover, these particles gathered inside interdendritic regions of the ternary Al-7Si-Zn alloys. The density, strength and hardness of Al-7Si-Zn alloys increased continuously with increasing zinc content, but their elongation to fracture and impact energy showed a reverse trend. It was also observed that zinc had no significant effect on the friction coefficient of the alloys, but their wear volume decreased with increasing zinc content up to 4%, above which the trend reversed. The wear surfaces of the alloys were characterized mainly by smearing layer with some degree of oxidation. In addition, delamination and fine scratches were observed on the worn surface. It was concluded that the addition of zinc up to 4% improves both mechanical and wear behaviour of Al-7Si alloy.
AtıfScopus48WoS41OpenAlex54
İncele - MakaleAçık Erişim2014Scopus SJRQ3Synthesis and spectral and thermal characterization of new metal-free and metallophthalocyanines: Investigation of their photophysical, photochemical, and thin film properties
Kaya, Elif Çelenk; Durmuş, Mahmut; Yanmaz, Ekrem; KantekiN, Halit
Novel tetrasubstituted metal-free (2), zinc (II) (3), cobalt (II) (4), and copper (II) (5) phthalocyanines bearing 2-phenylethanolate groups on the peripheral positions were synthesized by the cyclotetramerization reaction of the phthalonitrile derivative 1. The new compounds were characterized by a combination of IR, 1H NMR, 13 C NMR, UV-Vis, elemental analysis, and MS spectra data. The thermal stabilities of the phthalocyanine compounds were determined by thermogravimetric analysis. For metal-free (2) and zinc (3) phthalocyanines, photochemical (photodegradation and singlet oxygen quantum yields) and photophysical (fluorescence quantum yields and fluorescence lifetimes) properties were analyzed in dimethylsulfoxide (DMSO). The cobalt (4) and copper (5) phthalocyanines were not evaluated for this purpose because of their paramagnetic behavior. The metal-free (2) and zinc (3) phthalocyanines' fluorescence quenching behaviors were also investigated. The new phthalocyanine compounds' fluorescence emissions were effectively quenched by 1,4-benzoquinone in DMSO. The thin films of the cobalt phthalocyanine compound (4) were grown by electron beam evaporation technique. Crystalline CoPc (4) thin films were investigated by X-ray diffraction spectroscopy. Surface morphology of the CoPc (4) thin films was characterized by SEM.
AtıfScopus13WoS11OpenAlex15
İncele - MakaleAçık Erişim2014Scopus SJRQ2High order approximation of the inverse elliptic problem with dirichlet-neumann conditions
Ashyralyyev, Charyyar
Inverse problem for the multidimensional elliptic equation with Dirichlet-Neumann conditions is considered. High order of accuracy difference schemes for the solution of inverse problem are presented. Stability, almost coercive stability and coercive stability estimates of the third and fourth orders of accuracy difference schemes for this problem are obtained. Numerical results in a two dimensional case are given.
AtıfScopus35WoS31OpenAlex35İncele - MakaleYalnız künye2014Scopus SJRQ2K-Ar dating, whole-rock and Sr-Nd isotope geochemistry of calc-alkaline volcanic rocks around the Gümüşhane area: Implications for post-collisional volcanism in the Eastern Pontides, Northeast Turkey
Aslan, Zafer; Arslan, Mehmet; Temizel, Irfan; Kaygusuz, Abdullah
Volcanic rocks from the Gümüşhane area in the southern part of the Eastern Pontides (NE Turkey) consist mainly of andesitic lava flows associated with tuffs, and rare basaltic dykes. The K-Ar whole-rock dating of these rocks range from 37.62 ± 3.33 Ma (Middle Eocene) to 30.02 ± 2.84 Ma (Early Oligocene) for the andesitic lava flows, but are 15.80 ± 1.71 Ma (Middle Miocene) for the basaltic dykes. Petrochemically, the volcanic rocks are dominantly medium-K calc-alkaline in composition and show enrichment of large ion lithophile elements, as well as depletion of high field strength elements, thus revealing that volcanic rocks evolved from a parental magmas derived from an enriched mantle source. Chondrite-normalized rare-earth element patterns of the volcanic rocks are concave upwards with low- to-medium enrichment (LaCN/LuCN = 3.39 to 12.56), thereby revealing clinopyroxene- and hornblende-dominated fractionations for andesitic-basaltic rocks and tuffs, respectively. The volcanic rocks have low initial 87Sr/86Sr ratios (0.70464 to 0.70494) and εNd(i) values (+1.11 to +3.08), with Nd-model ages (TDM) of 0.68 to 1.02 Ga, suggesting an enriched lithospheric mantle source of Proterozoic age. Trace element and isotopic data, as well as the modelling results, show that fractional crystallization and minor assimilation played an important role in the evolution of the volcanic rocks studied. The Eocene to Miocene volcanism in the region has resulted from lithospheric delamination and the associated convective thinning of the mantle, which led to the partial melting of the subduction-metasomatized lithospheric mantle.
AtıfScopus66WoS51OpenAlex64İncele - MakaleYalnız künye2014Scopus SJRQ1The effects of macro synthetic fiber reinforcement use on physical and mechanical properties of concrete
Bolat, Hakan; Şimşek, Osman; Çullu, Mustafa; Durmuş, Gökhan; Can, Ömer
Attempts to find a construction material having increased strength, ductility, toughness, and durability have led to interest in high performance fiber reinforced concrete. The use of such materials increases day by day. When the fibers are distributed in a homogeneous way and used in appropriate quantity inside the concrete, they reduce cracks, contribute to tensile strength, toughness, ductility and durability, and improve other mechanical properties. In this study, four types of concrete were produced: steel fiber (SFRC), polyester fiber (PYFRC), polypropylene fiber (PPFRC) reinforced concrete and a reference sample made of plain concrete (R1); these were then compared to one another. The ratio of fibers was used 4.25% of volume of concrete. The effects of the different types of fiber on hardened concrete were determined by conducting physical and mechanical experiments. Compressive strength, surface hardness, ultrasonic pulse velocity, carbonation, abrasion, capillarity and freeze-thaw resistance experiments were conducted on hardened concretes. SFRC had higher 12.4%, PYFRC 3.4% higher and PPFRC 4.3% lower compressive strength with respect to R1. PPFRC showed 8.04% higher compressive strength than R1 when it was determined by the surface hardness method. SFRC showed 5.4% higher compressive strength than R1 when we applied the ultrasonic pulse velocity method. In the abrasion experiment, the highest abrasion was found in SFRC with ∼0.5%, while the lowest was found in PPFRC at ∼0.18%. The highest and lowest amount of capillary water absorption was seen in R1 and PYFRC, respectively. In a carbonation experiment, SFRC was determined ∼130.8% higher than R1. It was concluded that the types of fiber used for reinforcement influenced the physical and mechanical properties of the concrete.
AtıfScopus137WoS123OpenAlex147İncele - MakaleYalnız künye2014Scopus SJRQ1LA-ICP MS zircon dating, whole-rock and Sr-Nd-Pb-O isotope geochemistry of the Camiboǧazi pluton, Eastern Pontides, NE Turkey: Implications for lithospheric mantle and lower crustal sources in arc-related I-type magmatism
Kaygusuz, Abdullah; Arslan, Mehmet; Siebel, Wolfgang; Sipahi, Ferkan; Ilbeyli, Nurdane; Temizel, Irfan
Late Cretaceous I-type plutons are widespread in the Eastern Pontides, NE Turkey. The studied Camiboǧazi pluton is a composite pluton consisting of diorite, tonalite, monzodiorite, monzonite, quartz monzonite, granite, and mafic microgranular enclaves (MMEs). Laser ablation ICP-MS U-Pb dating of zircon yielded crystallization ages of 76.21±0.79Ma, 75.65±0.50Ma, 75.04±0.83Ma, and 74.73±0.86Ma for diorite, monzodiorite, monzonite, and granite, respectively. The rocks of the pluton have I-type, high-K to shoshonitic and metaluminous character, displaying whole-rock geochemical features of arc-related granites. They are enriched in large-ion lithophile and light rare-earth elements, and depleted in high-field-strength elements. Major element variations can be attributed to fractionation of plagioclase, clinopyroxene, hornblende, and Fe-Ti oxides. The rocks show considerable variation in 87Sr/86Sr(i) (0.70498 to 0.70622), εNd(i) (-2.79 to -0.36), δ18O values (+6.3 to +11.4) and Nd model ages (TDM) (0.81Ga to 1.26Ga). Besides, they have (206Pb/204Pb)=18.44-19.09, (207Pb/204Pb)=15.64-15.69, and (208Pb/204Pb)=38.37-38.89. Although isotope signatures of the mafic microgranular enclaves (MMEs) (87Sr/86Sr(i)=0.70551 to 0.70622; εNd(i)=-2.9 to -1.23; δ18O=+8.3 to +9.7) are largely similar to the host rocks, MMEs are characterized by relatively high Mg-numbers (32-36), low contents of SiO2 (52-56wt.%) and low ASI (0.7-0.9). Estimated crystallization temperatures for the rocks of the pluton range from 735±58°C to 844±24°C and a shallow intrusion depth (<10km) is estimated from Al-in-hornblende thermobarometry. Whole-rock geochemical and isotopic data suggest magma generation by dehydration melting of an amphibolite-type lower crustal component with additional input of a subcontinental lithospheric mantle component. Furthermore, Sr-Nd isotope mixing model reveals ~30% to 40% lower crustal magma contribution to the mantle component.
AtıfScopus87WoS76OpenAlex83İncele - MakaleYalnız künye2014Scopus SJRQ4Smoking habits and the related sociodemographic characteristics in university students; [Üniversite öǧrencilerinin sigara İçme davrani{dotless}şlari{dotless} ve İlişkili sosyodemografik özellikleri]
Özcebe, Hilal; Doǧan, Bahar Güçiz; Inal, Ebru; Haznedaroǧlu, Dilek; Bertan, Münevver
Objectives: Smoking is an important public health issue in Turkey. This study set out to investigate the smoking prevalence among first and fourth grade university students as well as the associated socio-demographic variables. Material And Methods: A survey was carried out by the International Children's Centre (ICC) in the faculties of Science and Literature, Education and Medicine of nine Turkish Universities to determine the knowledge and life styles of the 1st and 4th grade university students in adolescence (2009). A total of 5.221 students were evaluated. Data were analysed using SPPS 16.0-9907290 statistical package program. Results: The first grade students with illiterate mothers (23.0%), those who were living alone at home (37.7%) and those who considered receiving inadequate pocket money (24.9%) had a higher level of smoking prevalence (p<0.05). The fourth grade students with illiterate mothers (34.9%), those who were living with their friends (34.0%), those who perceived their economic situation bad (37.7%) and those who considered receiving inadequate pocket money (36.3%) had a higher level of smoking prevalence (p<0.05). Conclusion: A relationship between smoking habits of university students and some socio-demographic characteristics was found. We believe that more priority should be given to health promotion interventions among university students, especially among those of low socioeconomic status. On the other hand, in order to monitor the efficacy of smoking-related interventions among young people, there is a need for early detection of young individuals who are at risk and urgent interventions should be carried out.
AtıfScopus12WoS13OpenAlex18İncele - MakaleAçık Erişim2014Scopus SJRQ3Stereotactic Excision of Additional Lesions Detected with Intraoperative Ultrasound Examination During Radiofrequency Dissecting Sealar (Habib®) Assisted Hepatic Metastasectomy: Report of 4 Cases
Altuntas, Yunus E.; Unel, Sacide; Gezen, Fazli C.; Aksakal, Nihat; Civil, Osman; Vural, Selahattin; Ozates, Mustafa; Oncel, Mustafa
Intraoperative ultrasound has been using to achieve a proper resection strategy in patients undergoing a hepatic colorectal metastasectomy. This study aims to describe and reveal the place of stereotactic metastasectomy in nonpalpable colorectal liver metastases (CLM). A chart review was initiated for all patients underwent resection for CLM between 2006 and 2011. The data concerning perioperative data and intraoperative strategy were abstracted. Among the 58 patients, who underwent a resection for CLM, 4 (6.9 %) (all men, median age 65.5, range 49-72, years) necessitated a stereotactic metastasectomy. Preoperative evaluations showed 1 (n = 1), 2 (n = 2), or 3 (n = 1) lesions, and intraoperative ultrasound (IUS) found an additional lesion in a case. Stereotactic marking was performed for nonpalpable lesions located in segments IVA, II, and VI and at the junction of segments V and VI. The margins were negative for all lesions both resected with conventional and stereotactic techniques. The examinations of the stereotactic resection materials revealed metastatic adenocarcinoma (patients n = 2), focal nodular hyperplasia (n = 1), and abnormal benign liver histology probably induced by chemotherapy (n = 1). The median (range) operation and hospitalization periods were 217.5 (150-310) minutes and 5.5 (2-9) days. No complications were observed except biliary fistula in a case, which spontaneously disappeared within 2 weeks. A patient died due to systemic disease including hepatic metastases 33 months after the liver surgery. Stereotactic metastasectomy may be feasible for the removal of nonpalpable CLM. Further evaluations are necessitated to understand the accurate place of this novel technique.
- MakaleAçık Erişim2014Scopus SJRQ1Multiwalled CNT-pHEMA composite conduit for peripheral nerve repair
Arslantunali, D.; Budak, G.; Hasirci, V.
A nerve conduit is designed to improve peripheral nerve regeneration by providing guidance to the nerve cells. Conductivity of such guides is reported to enhance this process. In the current study, a nerve guide was constructed from poly(2-hydroxyethyl methacrylate) (pHEMA), which was loaded with multiwalled carbon nanotubes (mwCNT) to introduce conductivity. PHEMA hydrogels were designed to have a porous structure to facilitate the transportation of the compounds needed for cell nutrition and growth and also for waste removal. We showed that when loaded with relatively high concentrations of mwCNTs (6%, w/w in hydrogels), the pHEMA guide was more conductive and more hydrophobic than pristine pHEMA hydrogel. The mechanical properties of the composites were better when they carried mwCNT. Elastic modulus of 6% mwCNT loaded pHEMA was twofold higher (0.32 ± 0.06 MPa) and similar to that of the soft tissues. Electrical conductivity was significantly improved (11.4-fold) from 7 × 10-3 Ω-1.cm-1 (pHEMA) to 8.0 × 10-2 Ω-1.cm-1 (6% mwCNT loaded pHEMA). On application of electrical potential, the SHSY5Y neuroblastoma cells seeded on mwCNTs carrying pHEMA maintained their viability, whereas those on pure pHEMA could not, indicating that mwCNT helped conduct electricity and make them more suitable as nerve conduits.
AtıfScopus75WoS57OpenAlex75
İncele - MakaleYalnız künye2014Scopus SJRQ2Geochemical and Sr-Nd isotopic characteristics of Murgul (Artvin) volcanic rocks in the Eastern Black Sea Region (Northeast Turkey)
Sipahi, Ferkan; Sadiklar, M. Burhan; Şen, Cüneyt
The studied volcanic rocks are footwall and hanging wall dacites from the Murgul mine and the surrounding area. Moreover, the hanging wall dacites contain enclaves. Footwall dacite contains biotite, whereas hanging wall dacitic rocks contain hornblende as a ferromagnesian mineral. The enclaves in the hanging wall dacite have sizes that range from 1cm to 20cm and contain hornblende as a ferromagnesian mineral. The volcanic rocks show tholeiitic and transitional affinities. They are rich in large ion lithophile element and light rare earth element with pronounced depletion of high field strength elements. The chondrite-normalized rare earth element patterns (LaN/LuN=1.47-5.12) show low to medium enrichment, which reveal that the rocks were obtained from similar sources in Murgul volcanic rocks. The initial 87Sr/86Sr values range from 0.70442 to 0.70525, and the initial 143Nd/144Nd values range from 0.512741 to 0.512770. The main solidification processes involved in the evolution of the volcanic rocks consist of fractional crystallization with minor amounts of crustal contamination and magma mixing. All geochemical data support that these rocks originated from andesitic magma, and that the parental magma of the rocks were probably derived from an enriched upper mantle, previously modified by subduction-induced metasomatism in a geodynamic setting.
AtıfScopus28WoS26OpenAlex25İncele - MakaleYalnız künye2014Scopus SJRQ2A new 5,6-dihydro-2-pyrone derivative from Phomopsis amygdali, an endophytic fungus isolated from hazelnut (Corylus avellana)
Akay, Şeref; Ekiz, Güner; Kocabaş, Fatma; Hameş-Kocabaş, E. Esin; Korkmaz, Kemal S.; Bedir, Erdal
Aims of this study were to isolate endophytes from different parts of hazelnut - Corylus avellana L. to obtain bioactive secondary metabolites and search for the presence of gene region of taxadiene synthase (Ts), a key enzyme in taxol biosynthesis, on selected fungi. Fourteen fungal species were isolated and cultured for the screening studies. The cell-free fermentation broths were extracted with chloroform. The chloroform extracts were tested for cytotoxic activity by MTT method. Based on the activity results and chemical profiles, the isolate identified as Phomopsis amygdali by internal transcribed spaces (ITS) sequence analysis using ITS1 primer was selected for further studies. After large-scale fermentation and purification studies, two major compounds, one of which turned out to be a new secondary metabolite, were isolated and characterized. Structure of the new metabolite was elucidated as (S)-4-butoxy-6-((S)-1-hydroxypentyl)-5,6-dihydro-2H-pyran-2-one by the extensive use of 1D and 2D NMR, and HR-MS, whereas the known compound was identified as (-)pestalotin. Additionally, to evaluate taxol-producing potential of the selected isolate, a PCR amplification study followed by gel electrophoresis analysis was carried out revealing no Ts gene region.
AtıfScopus23WoS18OpenAlex24İncele - MakaleYalnız künye2014Scopus SJRQ1New thiophene-1,2,4-triazole-5(3)-ones: Highly bioactive thiosemicarbazides, structures of Schiff bases and triazole-thiols
Ünver, Yasemin; Sancak, Kemal; Çelik, Fatih; Birinci, Emrah; Küçük, Murat; Soylu, Serkan; Burnaz, Nesibe Arslan
Key compound 2-(4-amino-5-oxo-3-(thiophene-2-ylmethyl)-4,5-dihydro-1,2,4- tiazole-1-yl) acetohydrazide (3) was synthesized by reacting hydrazine hydrate with ethyl-2-(4-amino-5-oxo-3-(thiophene-2-ylmethyl)-4,5-dihydro-1,2,4-tiazole- 1yl)acetate (2), obtained in basic media from 4-amino-5-(thiophene-2-ylmethyl)- 2H-1,2,4-triazole-3(4H)-one (1). Compound 3 was converted to thiosemicarbazide derivatives (4a-d) and Schiff base derivatives 6a-e and 7a-e. The treatment of compound 4 with NaOH gave 4-amino-2-((4-(4-aryl)-5-mercapto-4H-1,2,4-triazole-3- yl)methyl)-5-(thiophene-2-ylmethyl)-2H-1,2,4-triazole-3(4H)-ones (5a-d). All newly compounds, well characterized by elemental analyses, IR, 1H NMR, 13C NMR and mass spectral studies were tested for their antioxidant and antimicrobial activities. Thiosemicarbazide derivatives (4a-d) were highly active in two antioxidant tests with 69.0-88.2% DPPH scavenging and 503-1257 μM TEAC values, while the others showed lower or no activity. The results of the two antioxidant tests correlated well. Moreover, Thiosemicarbazide derivatives (4a-d) also showed antibacterial activity against Staphylococcus aureus, Bacillus cereus, and Mycobacterium smegmatis. Thiosemicarbazide group deserves attention in the synthesis of bioactive compounds.
AtıfScopus109WoS110OpenAlex99İncele - MakaleAçık Erişim2014Scopus SJRQ3Preparation of a new sorbent, cetyltrimethylammonium bromide (CTAB)-modified obsidian, for the separation, preconcentration of Pb(II), Cd(II) ions in food and water samples
Ozdes, Duygu; Duran, Celai
Cetyltrimethylammonium bromide (CTAB)-modified obsidian (CTAB-OB) was utilized as a new sorbent for the separation and preconcentration of Pb(II) and Cd(II) ions by solid phase extraction in some environmental samples prior to their flame atomic absorption spectrophotometric determination. The characterization of CTAB-OB was performed by BET surface area,FTIR and SEM techniques. The effects of significant analytical parameters,including pH of the aqueous solution,eluent type,concentration and volume,CTAB-OB amount,sample volume,adsorption and desorption contact time,were evaluated in detail on the recovery of the analyte ions. The adsorption capacity of CTAB-OB was found to be 48.8 and 43.4 mg g-1 for the Pb(II) and Cd(II) ions,respectively. The detection limits for the analyte ions were 0.89 μg L-1 for Pb(II) and 0.37 μg L-1 for Cd(II),while the relative standard deviations were lower than 3.5% for both of them. In order to ensure the accuracy of the method,certified reference material (CRM-SA-C Sandy Soil C) analyses and spike tests were performed. Then the proposed method was applied to sea and stream water,black tea,and Turkish and import coffee samples to determine their Pb(II) and Cd(II) contents.
AtıfScopus7WoS7OpenAlex7İncele - MakaleAçık Erişim2014Scopus SJRQ1Dynamic mechanical spectra of selected turkish honeys: Construction of predictive models for complex viscosity using two different nonlinear modeling techniques
Kayacier, Ahmed; Yüksel, Ferhat; Karaman, Safa
Dynamic oscillatory shear rheological characteristics of honey samples from different floral sources were evaluated using frequency sweep test and stress sweep test at three different temperatures (10, 15, and 20°C). All honey samples showed liquid-like behavior because the loss modulus was significantly greater than the elastic modulus. Pine honey showed the highest complex viscosity (86.33 Pa s at 10°C), while the lowest complex viscosity was observed in citrus honey (22.15 Pa s) at the same temperature. Temperature dependency of complex viscosity of honey samples was modeled by Arrhenius model and activation energy values of honeys ranged from 83.13 to 97.46 kJ/mol. An efficient predictive model for complex viscosity values of honeys was constructed using adaptive neuro fuzzy inference system that showed satisfactory prediction performance with high coefficient of determination (0.995) and low root mean square error (0.04) in the validation period compared to artificial neural networks.
AtıfScopus8WoS8OpenAlex9İncele - MakaleYalnız künye2014Scopus SJRQ2Synthesis and carbonic anhydrase inhibitory effects of novel sulfamides derived from 1-aminoindanes and anilines
Akbaba, Yusuf; Bastem, Enes; Topal, Fevzi; Gülçin, Ilhami; Marasç, Ahmet; Göksu, Süleyman
Three 1-aminoindanes, four anilines and BnOH or t-BuOH were reacted with chlorosulfonyl isocyanate to give sulfamoyl carbamates. Pd-C catalysed hydrogenolysis reactions of carbamates or deprotection of the Boc group of the carbamates with CF3CO2H afforded seven novel sulfamides. Human carbonic anhydrase (hCA) isoenzymes I and II (hCA I and hCA II) were purified from fresh human blood erythrocytes with onestep affinity chromatography on Sepharose 4B-tyrosine-sulfanilamide. The inhibitory properties of the novel sulfamides on both isoenzymes were determined using the esterase activity with 4-nitrophenyl acetate (NPA) as substrate. The tested novel sulfamides derived from 1-aminoindanes and anilines effectively inhibited hCA I and II competitively in the nanomolar range. Among these compounds, the novel sulfamide derivative 17 showed themost potent inhibitory effect against hCA I (Ki: 153.88 nM), while sulfamide derivative 26 showed the highest inhibitory potential against hCA II (Ki: 117.80nM).
AtıfScopus89WoS88OpenAlex87İncele - MakaleYalnız künye2014Scopus SJRQ2Empirical findings on triplet deficits hypothesis: The case of Turkey
Şen, Ali; Şentürk, Mehmet; Sancar, Canan; Akbaş, Yusuf Ekrem
The aim of this study is to investigate the concept of triplet deficits in Turkey between 1980 and 2010. "Dolado-Lütkepohl Granger Causality Analysis" was performed in order to determine the direction of the relationship among the variables. In addition, the Vector Autoregressive (VAR), Variance Decomposition and Impulse-Response analysis were performed to determine the degree to which variables affected each other. The study finds that triplet deficit hypothesis was valid in Turkey between 1980 and 2010.
AtıfScopus8İncele - MakaleYalnız künye2014Scopus SJRQ2Determination of structural behavior of Bosporus suspension bridge considering construction stages and different soil conditions
Günaydin, Murat; Adanur, Süleyman; Altunişik, Ahmet Can; Sevim, Bariş; Türker, Emel
In this paper, it is aimed to determine the structural behavior of suspension bridges considering construction stages and different soil conditions. Bosporus Suspension Bridge connecting the Europe and Asia in Istanbul is selected as an example. Finite element model of the bridge is constituted using SAP2000 program considering existing drawings. Geometric nonlinearities are taken into consideration in the analysis using P-Delta large displacement criterion. The time dependent material strength of steel and concrete and geometric variations is included in the analysis. Time dependent material properties are considered as compressive strength, aging, shrinkage and creep for concrete, and relaxation for steel. To emphases the soil condition effect on the structural behavior of suspension bridges, each of hard, medium and soft soils are considered in the analysis. The structural behavior of the bridge at different construction stages and different soil conditions has been examined. Two different finite element analyses with and without construction stages are carried out and results are compared with each other. At the end of the analyses, variation of the displacement and internal forces such as bending moment, axial forces and shear forces for bridge deck and towers are given in detail. Also, displacement and stresses for bridge foundation are given with detail. It can be seen from the analyses that there are some differences between both analyses (with and without construction stages) and the results obtained from the construction stages are bigger. It can be stated that the analysis without construction stages cannot give the reliable solutions. In addition, soil condition have effect on the structural behavior of the bridge. So, it is thought that construction stage analysis using time dependent material properties, geometric nonlinearity and soil conditions effects should be considered in order to obtain more realistic structural behavior of suspension bridges.
AtıfScopus20WoS17OpenAlex19İncele - MakaleYalnız künye2014Scopus SJRQ2Assessment of kinetics, thermodynamics and equilibrium parameters of Cr(VI) biosorption onto Pinus brutia Ten
Ozdes, Duygu; Gundogdu, Ali; Kemer, Baris; Duran, Celal; Kucuk, Murat; Soylak, Mustafa
The aim of the present study was to investigate the sorption potential of pine bark (Pinus brutia Ten.) for removal of Cr(VI) ions from aqueous solutions. The biosorption characteristics of Cr(VI) ions onto bark biomass were examined with respect to the changes in initial pH of the solution, contact time, initial Cr(VI) and bark concentration, bark particle size, temperature, etc. The biosorption isotherms were described by means of Langmuir and Freundlich models and the biosorption kinetics were analysed using pseudo-first-order, pseudo-second-order and intraparticle diffusion models. The thermodynamic parameters proved that the process was feasible, spontaneous and endothermic in nature.
AtıfScopus34WoS29İncele - MakaleYalnız künye2014Scopus SJRQ2Influence of wall flexibility on dynamic response of cantilever retaining walls
Cakir, Tufan
A seismic evaluation is made of the response to horizontal ground shaking of cantilever retaining walls using the finite element model in three dimensional space whose verification is provided analytically through the modal analysis technique in case of the assumptions of fixed base, complete bonding behavior at the wall-soil interface, and elastic behavior of soil. Thanks to the versatility of the finite element model, the retained medium is then idealized as a uniform, elastoplastic stratum of constant thickness and semi-infinite extent in the horizontal direction considering debonding behavior at the interface in order to perform comprehensive soil-structure interaction (SSI) analyses. The parameters varied include the flexibility of the wall, the properties of the soil medium, and the characteristics of the ground motion. Two different finite element models corresponding with flexible and rigid wall configurations are studied for six different soil types under the effects of two different ground motions. The response quantities examined incorporate the lateral displacements of the wall relative to the moving base and the stresses in the wall in all directions. The results show that the wall flexibility and soil properties have a major effect on seismic behavior of cantilever retaining walls and should be considered in design criteria of cantilever walls. Furthermore, the results of the numerical investigations are expected to be useful for the better understanding and the optimization of seismic design of this particular type of retaining structure.
AtıfScopus16WoS16OpenAlex18İncele - MakaleYalnız künye2014Scopus SJRQ2Exergetic analysis of using the gaseous fuels in spark ignition engines
Sezer, Ismet; Bilgin, Atilla
This paper aims to investigate the use of alternative gaseous fuels in spark ignition engines via an exergy analysis. A quasi-dimensional two-zone thermodynamic cycle model is used for this purpose. The intake and exhaust processes are computed by a simple approximation method, and the processes (that is, compression, combustion, and expansion) are simulated in detail. The turbulent flame propagation process is used for the combustion simulation. The second law of thermodynamics is applied to the cycle model to perform the exergy analysis. The exergy transfers associated with heat, work, and exhaust; the irreversibilities, thermomechanical exergy, fuel chemical exergy, and total exergy have been computed in the exergy analysis. A distribution of the fuel exergy, the energy-based (the first law) efficiency, and the exergetic (the second law) efficiency were also calculated during the exergy analysis. Thus, the effects of using natural gas and liquefied petroleum gas on the exergetic terms and the efficiencies are investigated. The results of the study show that investigated alternative gaseous fuels have affected the variations in the exergy transfers, irreversibilities, and efficiencies. The gaseous fuels are suitable from the exergy point of view because of the lessened exergy destruction rate, but they suffer from the engine performance reduction.
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