ANP application for evaluating Turkish mobile communication operators

The proposed decision model, based on Analytic Network Process (ANP), has been developed in order to determine the dynamics of the Global System for Mobile Communications (GSM) market. In accordance with the sequence of ANP, first of all, the problem was structured and modeled. At the next step, a quantitative analysis was conducted with the customers in order to assess the importance of the related factors and forecast the market shares of the Turkish mobile communication operators. The forecasted market share values were compared with actual ones for the validation of the decision model. The assessed importance of the factors in a valid model would be a potential competitive advantage for the mobile operators.     

Affine model of inflation-indexed derivatives and inflation risk premium

This paper proposes an affine-based approach which jointly captures the nominal interest rate, the real interest rate, and the inflation risk premium to price inflation-indexed derivatives, including zero-coupon inflation-indexed swaps, year-on-year inflation-indexed swaps, inflation-indexed swaptions, and inflation-indexed caps and floors. We provide an example and explain how to use traded zero-coupon inflation-indexed swap rates to estimate inflation risk premiums.     

A high sensitive assay platform based on surface-enhanced Raman scattering for quantification of protease activity

In this study, a new, sensitive, and rapid assay was developed to quantitatively measure the proteolytic enzyme activity using the surface-enhanced Raman scattering (SERS) probe. Two different shapes of gold nanoparticles, gold nanosphere and nanorod particles were produced. SERS label, comprising self-assembled monolayers (SAMs) of Raman reporter molecule (5,5-Dithiobis (2-Nitrobenzoic acid), DTNB), was coated on the surface of the nanoparticles. Two different SERS-based analysis platforms were designed using gold-coated glass slide and polystyrene microtiter plate. The calibration curves were obtained by plotting the intensity of the SERS signal of symmetric NO₂ stretching of DTNB at 1326 cm⁻¹vs. the protease concentration. The effects of nanoparticle geometry and assay platform on the protease assay were investigated and the best working combination of the parameters was selected as rod shaped SERS probe and gold-coated glass slide. The correlation between the protease activity and SERS signal was found to be linear within the range of 0.1-2 mU/mL (R² = 0.979). The limit of detection (LOD) and limit of quantification (LOQ) values of the validated method were found as 0.43 and 1.30 mU/mL, respectively. The intra-day and inter-day precisions of the method, as relative standard deviation (RSD), were determined as 2.5% and 3.6%, respectively. The developed method was successfully applied for quantitative analysis of the commercial enzyme preparate that is used in cheese making process. It was also used for investigation of substrate specificity of protease enzyme towards the casein and bovine serum albumin. The proposed method has a flexibility to try different substrates for the detection of various enzyme activities.     

Constituents of Salvia microphylla

A new phenolic ester 2-( p-hydroxyphenyl)ethyl eicosaheptanoic acid ester (1) and a known one hexacosylferulate (2) were isolated from the acetone extract of Salvia microphylla. In addition, two sesquiterpenes beta-eudesmol (3) and 8alpha-hydroxy-beta-eudesmol (4), a diterpene carnosic acid 12-methyl ether (12-methoxycarnosic acid) (5), three triterpenes erithrodiol 3-acetate, oleanolic acid, lupeol and beta-sitosterol were obtained as known compounds from this plant extract. The structures of the isolated compounds were elucidated by spectroscopic methods, including one- and two- dimensional 1H- and 13C-NMR and MS spectroscopies. The selected compounds were tested for antimicrobial activity against standard bacterial strains, and only carnosic acid 12-methyl ether showed antimicrobial activity against S. aureus at 78 microg mL(-1).     

On homology of real algebraic varieties

Let be a commutative ring with unity and an -oriented compact nonsingular real algebraic variety of dimension . If is any nonsingular complexification of , then the kernel, which we will denote by , of the induced homomorphism is independent of the complexification. In this work, we study and give some of its applications.

     

Solid-state Electrochemical Sensor Based on a Cross-linked Copper(II)-doped Copolymer and Carbon Nanotube Material for Selective and Sensitive Detection of Monohydrogen Phosphate

A novel solid-state electrochemical sensor based on a newly synthesized cross-linked copper(II) doped-copolymer and carbon nanotube material was developed for the direct determination of monohydrogen phosphate ions (HPO₄²⁻). The synthesized copolymers were characterized by FTIR, XPS, TG/DTG-DTA and SEM techniques. The sensor had a Nernstian slope:-30.7±0.4 mV/decade, linear concentrations range: 1.0×10⁻⁶ - 1.0×10⁻¹ M, detection limit: 6.5×10⁻⁷ M, response time: 4 s and life time: 17 weeks. The sensor displayed constant potentials in the pH range 7.0-9.5. The sensor was successfully used as an indicator electrode in potentiometric titration and the direct determination of HPO₄ ²⁻ in water samples.     

Solvothermal synthesis and characterization of coordination polymers of cobalt(II) and zinc(II) with succinic acid

The complexes [Co(C₄H₄O₄)]_n (1) and [Zn(im)₂(C₄H₄O₄)]_n (2) (C₄H₄O₄ = succinate dianion, suc; im = imidazole) have been synthesized solvothermally and characterized by elemental analysis, IR, TG–DTA, and single-crystal X-ray diffraction techniques. Complex 1 is the first anhydrous member of the cobalt succinate family and has high thermal stability under a static air atmosphere, up to 425 °C, and complex 2 is a 1D coordination polymer. In addition, a new synthesis method and some properties of the known [Co(HCOO)₂·2H₂O]_n (3) complex are reported. After in situ synthesis of 3 via decomposition of DMF at 140 °C, it was found that complex 3 can adsorb some solvents repeatedly and is selective for H₂O.     

Photoinduced rearrangement of aromatic N-chloroamides to chloroaromatic amides in the solid state: inverted Π(N)-Σ(N) occupational stability of amidyl radicals

We report a solid-state photochemical rearrangement reaction by which aromatic N-chloroamides exposed to UV light or sunlight are rapidly and efficiently converted to chloroaromatic amides. The course, the intermediate (nascent chlorine vs dichlorine) and the outcome of the reaction depend on the excitation (exposure time, wavelength, and intensity) and on inherent structural factors (the directing role of the substituents and, as demonstrated by the different reactivity of two polymorphs of N-chlorobenzanilide, the supramolecular structure). The photolysis of the chloroamides provides facile photochemical access to arylamidyl radicals as intermediates, which in the absence of strong hydrogen bond donors are stabilized in the reactant crystals by C-H/N-Cl···π interactions, thus, providing insight into their structure and chemistry. Thorough theoretical modeling of the factors determinant to the stability and the nature of the spin-hosting orbital evidenced that although the trans-Π(||) state (Np spin) of the amidyls is normally preferred over the trans-Σ(⊥) configuration (Nsp(2) spin), stabilization by aromatic conjugation, steric and geometry factors, as well as by electronic effects from the substituents can decrease the Π-Σ gap in these intermediates significantly, resulting in similar and, in the case of the orthogonal amide-phenyl disposition, even reversed population of the unpaired electron in the two orbitals. Quantitative correlation established that the inverted occupational spin stability and the Π(N)-Σ(N) crossover are collectively facilitated by the conformation, valence angle, and disposition of the amide group relative to the aromatic system. The stabilization and detection of a trans-Σ(⊥) radical was experimentally accomplished by steric locking of the orthogonal trans-amide conformation with double ortho-tert-butyl substitution at the phenyl ring. The effects of the single para-phenyl substituents on the relative occupational stability of the arylamidyl radical states point out to non-Hammett behavior. By including cumulative electronic effects from multiple substitutions, four distinct families of the aromatic amidyl radicals were identified. The Π(∥) state is the most stable structure of the N-phenylacetamidyl radical and of most of the substituted arylamidyls, although the Σ(⊥) and Π(⊥) states can also be stabilized by introducing tert-butyl and nitro groups, respectively.     

Amperometric Phenol Biosensor Based on Horseradish Peroxidase Entrapped PVF and PPy Composite Film Coated GC Electrode

Polyvinylferrocene (PVF) was used as a mediator for the fabrication of a horseradish peroxidase (HRP)-modified electrode to detect phenol derivatives via a composite polymeric matrix of conducting polypyrrole (PPy). Through an electropolymerization process, enzyme HRP was entrapped with PPy in a three-electrode system onto a glassy carbon electrode previously covered with PVF, resulting in a composite polymeric matrix. Steady-state amperometric measurements were performed at ?200 mV vs. Ag/AgCl in aqueous phosphate buffer containing NaCl 0.1 M (pH 6.8) in the presence of hydrogen peroxide. The response of the HRP-modified PVF electrode was investigated for various phenol derivatives, which were 4-chlorophenol, phenol, catechol, hydroquinone, 2-aminophenol, pyrogallol, m-cresol, and 4-methoxyphenol. Analytical parameters for the fabricated PVF electrode were obtained from the calibration curves. The highest sensitivity was obtained from the calibration of 4-chlorophenol as 29.91 nA/μM. The lowest detection limit was found to be 0.22 μM (S/N?=?3) for catechol, and the highest detection limit was found to be 0.79 μM (S/N?=?3) for 4-methoxyphenol among the tested derivatives. The biosensor can reach 95% of steady-state current in about 5 min. The electrode is stable for 2 months at 4 °C.