HPLC-DAD–MS Analysis of Anthocyanins in Rose Wine Made From cv. Öküzgözü Grapes,and Effect of Maceration Time on Anthocyanin Content

The anthocyanin composition of rose wine made from cv. Öküzgözü, a variety of grape native to Turkey, and the effect of maceration time (3, 6, 12, 18, or 24 h) on the anthocyanin content of the wine have been investigated. High-performance liquid chromatography with diode-array detection (HPLC-DAD) and mass spectrometry (MS) were used for anthocyanin analysis. Thirteen different anthocyanins, including five glucosides, five acetyl glucosides, and three coumaroyl glucosides were identified and quantified. It was found that an important characteristic of Öküzgözü rose wine was the presence of a large amount of malvidin-3-glucoside and its acylated esters. The total anthocyanin content of the wine increased with increasing maceration time. On the basis of sensory analysis, the most preferred wine was that produced with 3-h maceration, because of its better color and general flavor attributes.     

Intermolecular interactions in (arene)chromium carbonyl compounds: prediction of chiral crystal packing from racemate structure

Six X-ray crystal structures are reported, all containing substituted triphenylmethanol derivative 4 either alone or as its mono or bis(chromium tricarbonyl) complexes. All four chromium complexes studied crystallize with two independent molecules in the crystallographic asymmetric unit. It is demonstrated that from the X-ray crystal structure of the acentric racemic (+/-)-(1pR,1' 'R)(1pS,1' 'S)-[Cr(CO)(3)(eta(6)-t-BuC(6)H(3)(CMeOMe)CPh(2)OH)], (+/-)-3, it is possible to deduce the 4-fold helical structure of the chiral (-)-(1pR,1' 'R) isomer, (-)-3. The bimetallic derivatives demonstrate the ability to control intermolecular interactions by the positioning of relative stereochemistry.     

Synthesis,Characterization and Electrorheological Properties of Polyindene/Kaolinite Composites

In this study, synthesis, characterization and electrorheological (ER) properties of polyindene (PIN) and polyindene/kaolinite composites were carried out by cationic radical polymerization using FeCl₃ as the oxidizing agent. The homopolymer and composites, containing different amounts of PIN were characterized by FTIR spectroscopy, thermo‐gravimetric (TGA) analyses, scanning electron microscopy (SEM) and dynamic light scattering (DLS) methods. The conductivity and dielectric properties of PIN and PIN/kaolinite composites were determined. Suspensions of PIN and PIN/kaolinite composites were prepared in silicone oil (SO), at a series of concentrations (c=5–25 m/m %). The effects of concentration, shear rate, electric field strength, frequency, temperature and promoter on ER activities of suspensions were investigated.     

An experimental investigation of wear of glass fibre-epoxy resin and glass fibre-polyester resin composite materials

In this paper, the effects of resin content on the wear of woven roving glass fibre-epoxy resin and glass fibre-polyester resin composite materials have been examined. Furthermore, composite materials are experimentally investigated under different loads and speeds by using a block-on-shaft wear tester. The influences of two thermosetting resins epoxy and polyester on the wear of glass-woven roving reinforced composites under has been investigated dry conditions. The glass fibre-epoxy resin and the glass fibre-polyester resin composite materials specimens have been tested under different experiment conditions. Tests were conducted for 0.39 and 0.557 m/s speeds, at two different loads of 5 and 10 N. The weight losses were measured after measuring different sliding distances. Wear in the experiments was determined as weight loss. For each experiment, one specimen was used. The amount of wear was measured before the experiment and after the experiment with the apparatus of balance scales with the accuracy of 10⁻³ g. Glass fibre-epoxy resin composites generally showed higher strength and minimum wear when compared with glass fibre-polyester resin composites materials. In addition, Scanning electron microscopy (SEM) is used to study the worn surface to verify the results.     

A nonstandard finite difference method for solving a mathematical model of HIV-TB co-infection

We design and analyze an unconditionally convergent nonstandard finite-difference method to study transmission dynamics of a mathematical model of HIV-TB co-infection. The dynamics of this model are studied using the qualitative theory of dynamical systems. These qualitative features of the continuous model are preserved by the numerical method that we propose in this paper. This method also preserves positivity of the solution which is one of the essential requirements when modelling epidemic diseases. Furthermore, we show that the numerical method is unconditionally stable. Competitive numerical results confirming theoretical investigations are provided. Comparisons are also made with other conventional approaches that are routinely used to solve these types of problems.     

HPLC determination of organic acids, sugars, phenolic compositions and antioxidant capacity of orange juice and orange wine made from a Turkish cv. Kozan

Organic acids, sugars, phenolic compositions and antioxidant capacities of orange juice and orange wine obtained from the cv. Kozan of Turkey were determined. High-performance liquid chromatographic methods were used to identify and quantify of these compounds. Three organic acids (citric, malic and ascorbic acids) and three sugars (sucrose, glucose and fructose) were determined. The major organic acid was found as citric acid. With regard to sugars, sucrose was present in the largest amounts for orange juice and wine. A total of 13 phenolic compounds were identified and quantified in orange juice and wine, including hydroxybenzoic acids (2), hydroxycinnamic acids (5), and flavanones (6). Hesperidin, narirutin and ferulic acid were the most abundant phenolic compounds in orange juice and wine. Antioxidant activities of orange juice and wine were measured using the DPPH^• (2,2-diphenyl-1-picrylhydrazyl) assay, and the antioxidant capacity of orange juice was found to be higher than that of orange wine.     

Platinum(II)-catalyzed intramolecular cyclization of alkynylbenzonitriles: synthesis of 1-alkoxyisoquinolines and isoquinolones

A facile synthesis of a series of 1-alkoxyisoquinolines and (2H)-isoquinolones by an intramolecular 6-endo-dig cyclization of ortho-alkynylbenzonitriles in the presence of a catalytic amount of hydrido(dimethylphosphinous acid-κP)[hydrogen bis(dimethylphosphinito-κP)]platinum(II) in various alcohols at 65-90 °C is described for the first time.     

Synthesis and characterization of ZnO thin films by thermal evaporation

ZnO thin films have been successfully synthesized by thermal evaporation of pure zinc at 900 °C under the flow of different percentages of argon and oxygen gases. The films were characterized by X-ray diffraction (XRD), variable pressure scanning electron microscopy (VPSEM), energy dispersive X-ray spectroscopy (EDS) and UV–vis spectroscopy. The aim of this paper is to study the influence of the oxygen percentage on the structural and morphological properties of the ZnO films. VPSEM results show that very thick needle structures were produced at high oxygen percentages. EDS results revealed that only Zn and O are present in the sample, indicating a composition of pure ZnO. XRD results showed that the ZnO synthesized under different quantities of oxygen were crystalline with the hexagonal wurtzite structure. UV–vis spectroscopy results indicated that the optical band gap energies from the transmission spectrum are between 3.62 and 3.69 eV for ZnO thin films.     

Catalytic Asymmetric Chlorination of β‐Keto Esters with Hypervalent Iodine Compounds

(Dichloroiodo)toluene (=dichloro(4‐methylphenyl)iodine; 2 ) was found to be a suitable chlorinating agent in the catalytic asymmetric chlorination of β‐keto esters 3 catalyzed by the [Ti(TADDOLato)] complex 1 (=bis(acetonitrile)dichloro[(4R,5R)‐2,2‐dimethyl‐α,α,α′,α′‐tetra(naphthalen‐1‐yl)‐1,3‐dioxolane‐4,5‐dimethanolato(2?)‐κO,κO′]titanium), whereby α‐chlorinated products were obtained in moderate to good yields and enantioselectivities of up to 71% (Scheme 2, Table 2). The enantioselectivity of the reaction shows a remarkable temperature dependence, the maximum selectivity being obtained at ca. 50°.     

In situ generation of the Coates catalyst: a practical and versatile catalytic system for the carbonylation of meso-epoxides

A highly active catalytic system for the carbonylation of meso- and terminal epoxides to β-lactones is described. The active catalyst, analogous to Coates' catalyst, is generated in situ from commercially available (TPP)CrCl and Co(2)(CO)(8). This practical system circumvents the preparation of air sensitive cobaltate salts, operates at low catalyst loadings, and allows the carbonylation of functionalized, sterically demanding and heterocyclic meso-epoxides.