PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7645
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Article Citation - WoS: 150Citation - Scopus: 7Correlation of Tunneling Spectra in Bi2sr2cacu2o8+? With the Resonance Spin Excitation(American Physical Society, 2001) Zasadzinski, John F.; Özyüzer, Lütfi; Miyakawa, Nobuaki; Gray, Kenneth E.; Hinks, David G.; Kendziora, Christopher A.New break-junction tunneling data are reported in Bi2Sr2CaCu2O8+δ over a wide range of hole concentration from underdoped (Tc=74k) to optimal doped (Tc=95k) to overdoped (Tc=48k). The conductances exhibit sharp dips at a voltage, Ω/e, measured with respect to the superconducting gap. Clear trends are found such that the dip strength is maximum at optimal doping and that Ω scales as 4.9kTc over the entire doping range. These features link the dip to the resonance spin excitation and suggest quasiparticle interactions with this mode are important for superconductivity.Article Citation - WoS: 16Citation - Scopus: 19Nmr Studies on Natural and Synthetic Amavadin(Elsevier Ltd., 2000) Armstrong, Elaine M.; Collison, David; Ertok, Nigar; Garner, Catherine D.The stereochemistry of isolated natural product Amavadin, which contains a 1:2 complex of V(IV) with N-hydroxyimino-2,2′-dipropionic acid (HIDPAH3), and some synthetic complexes have been investigated. Amavadin was isolated from Amanita muscaria and oxidized with [NH4]2[Ce(NO3)6]. H2[Δ-V(S,S-HIDPA)2].3H2O, H2[Δ,Λ-V(S,S-HIDPA)2].3H2O and their equivalent oxidized species have been synthesized and characterized spectroscopically. A combination of COSY, NOE, 1H, 13C-NMR and CD spectroscopy have been used to prove that the isolated natural product Amavadin consists of an almost equal mixture of the Δ- and Λ-isomers of [V(S,S-HIDPA)2]2-. The stereochemistry of isolated natural product Amavadin, which contains a 1:2 complex of V(IV) with N-hydroxyimino-2,2'-dipropionic acid (HIDPAH3), and some synthetic complexes have been investigated. Amavadin was isolated from Amanita muscaria and oxidized with [NH4]2[Ce(NO3)6]. H2[Δ-V(S,S-HIDPA)2].3H2O, H2[Δ,Λ-V(S,S-HIDPA)2].3H2O and their equivalent oxidized species have been synthesized and characterized spectroscopically. A combination of COSY, NOE, 1H, 13C-NMR and CD spectroscopy have been used to prove that the isolated natural product Amavadin consists of an almost equal mixture of the Δ- and Λ-isomers of [V(S,S-HIDPA)2]2-.Article Citation - WoS: 273Citation - Scopus: 327Transesterification of Nannochloropsis Oculata Microalga's Lipid To Biodiesel on Al2o3 Supported Cao and Mgo Catalysts(Elsevier Ltd., 2009) Umdu, Emin Selahattin; Tuncer, Mert; Şeker, ErolIn this study, we present the activities of Al2O3 supported CaO and MgO catalysts in the transesterification of lipid of yellow green microalgae, Nannochloropsis oculata, as a function of methanol amount and the CaO and MgO loadings at 50 °C. We found that pure CaO and MgO were not active and CaO/Al2O3 catalyst among all the mixed oxide catalysts showed the highest activity. Not only the basic site density but also the basic strength is important to achieve the high biodiesel yield. Biodiesel yield over 80 wt.% CaO/Al2O3 catalyst increased to 97.5% from 23% when methanol/lipid molar ratio was 30.Article Citation - WoS: 16Citation - Scopus: 21Ph- and Electro-Responsive Characteristics of Silk Fibroin-Hyaluronic Acid Polyelectrolyte Complex Membranes(Elsevier Ltd., 2009) Malay, Özge; Batıgün, Ayşegül; Bayraktar, OğuzpH-responsiveness of recently developed silk fibroin (SF) and hyaluronic acid (HA) polyelectrolyte complex (PEC) membranes and their potential use in electro-responsive drug release systems were investigated. PEC membranes were prepared within a narrow pH window (3.0-3.5) for a SF-HA weight ratio of 20 and they were characterized by Atomic Force Microscopy in addition to characterization studies previously reported by our group. Swelling kinetics of the membranes was studied for a pH window of 2.5-7.4 and cyclic swelling test was performed to determine the pH-responsiveness of the membranes. It was shown that membranes swelled more in alkaline conditions and responded to variations in pH of the medium. Electric-stimuli assisted drug permeation and release studies were performed with a custom-made diffusion cell under both passive condition and electric field applied in pulsatile fashion. The instantaneous flux raised as the current was applied and then declined when the current application was terminated, and this process was repeated on subsequent applications. SF-HA complex membranes were found promising for the electric-stimuli-sensitive release of a high molecular weight and charged model drug for a membrane-permeation controlled formulation.Article Citation - WoS: 35Citation - Scopus: 37Dirac Neutrino Masses From Generalized Supersymmetry Breaking(American Physical Society, 2008) Demir, Durmuş Ali; Everett, Lisa L.; Langacker, PaulWe demonstrate that Dirac neutrino masses in the experimentally preferred range are generated within supersymmetric gauge extensions of the standard model with a generalized supersymmetry breaking sector. If the superpotential neutrino Yukawa terms are forbidden by the gauge symmetry [such as a U(1)′], sub-eV scale effective Dirac mass terms can arise at tree level from hard supersymmetry breaking Yukawa couplings, or at one loop due to nonanalytic soft supersymmetry breaking trilinear scalar couplings. The radiative neutrino magnetic and electric dipole moments vanish at one-loop order.Article Citation - WoS: 262Citation - Scopus: 286Dye Adsorption Behavior of Luffa Cylindrica Fibers(Elsevier Ltd., 2008) Demir, Hasan; Top, Ayben; Balköse, Devrim; Ülkü, SemraUsing natural Luffa cylindrica fibers as adsorbent removal of methylene blue dye from aqueous solutions at different temperatures and dye concentrations was investigated in this study. Thermodynamics and kinetics of adsorption were also investigated. The adsorption isotherms could be well defined with Langmuir model instead of Freundlich model. The thermodynamic parameters of methylene blue (MB) adsorption indicated that the adsorption is exothermic and spontaneous. The average MB adsorption capacity was found out as 49 mg/g and average BET surface area of fibers was calculated as 123 m2/g.Article Citation - WoS: 120Citation - Scopus: 135Authentication of Pomegranate Juice Concentrate Using Ftir Spectroscopy and Chemometrics(Elsevier Ltd., 2008) Vardin, Hasan; Tay, Abdullatif; Özen, Fatma Banu; Mauer, LisaFourier transform infrared (FTIR) spectroscopy and chemometric techniques were used to detect the adulteration of pomegranate juice concentrate (PJC) with grape juice concentrate (GJC). The main differences between PJC and GJC infrared spectra occurred in the 1780-1685 cm-1 region, which corresponds to C{double bond, long}O stretching. Principal component analysis of the spectra was used to: (1) differentiate pure PJC and GJC samples and (2) classify adulterated (containing 2-14% vol/vol GJC) and pure PJC samples. Two principal components explained 99% of the variability in each of these applications. Partial least square analysis of the spectra resulted in prediction of the GJC adulterant concentration in PJC with a correlation coefficient, R2, of 0.9751. Partial least square analysis of spectra could also predict % titratable acidity and total solids in PJC with correlation coefficients of 0.9114 and 0.9916, respectively. Therefore, FTIR and chemometrics provide a useful approach for authenticating pomegranate juice concentrate.Article Citation - WoS: 34Citation - Scopus: 36Acclimation To Heat During Incubation. 2. Embryo Composition and Residual Egg Yolk Sac Fatty Acid Profiles in Chicks(Elsevier, 2008) Yalçın, S.; Bağdatlıoğlu, Neriman; Bruggeman, V.; Babacanoglu, E.; Uysal, İlke; Buyse, J.; Decuypere, E.; Siegel, P. B.The aim of the research was to evaluate embryo composition and changes in egg yolk fatty acid composition during embryonic development as a function of incubation temperature and age of breeders. Eggs obtained from a common breeder stock at 3 ages: 32 (younger), 42 (mid age), and 65 (older) wk were divided into 2 groups and placed into 2 incubators: the control and the second where eggs were heat-acclimated (HA) at 38.5°C for 6 h daily from d 10 to 18 of incubation. Body composition of embryos and chicks were measured on d 14, 18, and at hatch, respectively. Fatty acid profiles of yolk and residual egg yolk sac of chicks were analyzed before incubation and at hatch, respectively. Moisture content of embryos was highest on d 14 and then decreased regardless of parental age and incubation temperature. Moisture content of chicks at hatch from 42- and 65-wk parents were lower than those of chicks from 32-wk parents, whereas the trend in chick fat content was opposite. Incubation temperature had no effect on composition of chicks. Consistently lower cis-4,7,10,13,16,19- eicosapentaenoic (docosahexaenoic acid, DHA; 22:6n-3) and cis-11,14,17- eicosatrienoic (20:3n-3) fatty acids in the residual yolk sac of chicks than in egg yolks before incubation may have resulted from preferential uptake from the yolk. The DHA content in the residual yolk sac was considerably higher in chicks from older parents incubated at HA, whereas, in contrast, levels of 18:3n-3 were lower. Also, chicks from younger parents in the HA treatment had lower transported 18:3n-3 and higher levels of transported DHA. It may be concluded that this process observed during the high incubation temperature may be related to a protective strategy and thus contributes to postnatal heat adaptation.Article Citation - WoS: 16Citation - Scopus: 17Protective Effect of Zinc on Cyclophosphamide-Induced Hematoxicity and Urotoxicity(Humana Press, 2008) Ayhancı, Adnan; Uyar, Ruhi; Aral, Erinç; Kabadere, Selda; Appak, SılaCyclophosphamide (CP) is widely used for the treatment of neoplastic diseases; however, its toxicity causes dose-limiting side effects. Zinc (Zn) is an essential trace element and has important biological functions that control many cell processes including DNA synthesis, normal growth, reproduction, fetal development, bone formation, and wound healing. Therefore, the toxicity of CP and the possible protective effect of Zn on blood cells, bone marrow, and bladder of rat were investigated in this study. Intraperitoneal administration of 50, 100, or 150 mg/kg CP for 3 days caused, in a dose-dependent manner, reductions in the number of leukocytes, thrombocytes, and bone marrow nucleated cells and a serious urotoxicity. To explore whether CP-induced damages could be prevented by Zn, other groups of rats were pretreated with 4 or 8 mg/kg ZnCl2 intraperitoneally for 3 days then challenged with respective doses of CP plus ZnCl2 on day 4 for three more days. The results indicated that treatment of rats with Zn could dose-dependently alleviate CP-induced toxicities on blood cells, bone marrow cells, and urinary bladder. We suggest that Zn could be a potentially effective drug in the prevention of CP-related hematoxicity and urotoxicity.Article Citation - WoS: 14Citation - Scopus: 15Neutralization of an Extremely Acidic Sludge and Stabilization of Heavy Metals in Flyash Aggregates(Elsevier Ltd., 2007) Polat, Mehmet; Güler, Erkan; Lederman, Eli; Cohen, HaimAn extremely acidic, heavy metal-rich sludge (pH = -1.2) was scrubbed with a Class-F fly ash in order to simultaneously neutralize the acidity and stabilize the heavy metals contained in both wastes. This paper outlines the leaching behavior of the aggregate material generated by scrubbing. For proper fly ash/sludge ratios, the fly ash acted as an outstanding neutralizer for the acidic waste. Leaching of heavy metals from the aggregate samples was below the environmental limits within a pH range between 3 and 9. Subsequent washing of the leached aggregate with acidic CALWET solutions did not result in an additional release of heavy metals. It is proposed that coordinative bonding of the metal cations onto neutral surface sites and electrostatic adsorption led to stabilization of the heavy metals within the aggregate structure below hydrolysis pHs.