Evaluation of model compounds–polypropylene film interactions by Fourier transformed infrared spectroscopy (FTIR) method

The interactions of methyl esters, methyl ketones and aldehyde compounds with polypropylene (PP) film were investigated. PP film, placed on a glass vial, was immersed in aqueous solution containing a model flavour compound. After a determined time at 45°C, the PP film was analysed by Fourier transform infrared spectroscopy (FTIR), allowing us to follow the speed of sorption and to quantify its relative rate. For PP films, we observed that the sorption strongly depended on the structure of sorbed molecules. For each functional group of flavour compounds, the sorption increased as the carbon chain number increased. A linear chain of 12–14 carbons favours the sorption more than a linear chain of eight carbons. Concerning functions, the rate of sorption usually decreases from esters to ketones and to aldehydes. High sorption was observed for flavour compounds with a low difference of solubility parameter (SP) value between the film and flavour [(δ_polymer ? δ_flavour)² value]. Furthermore, by using the proposed thermodynamic affinity concept, represented as the contribution of three interactive molecular forces [dispersion (d_d), polar (d_p) and hydrogen bonding (d_h)] between two SP values of film and flavour, packaging materials with high flavour preservation against sorption can be designed. We have a good correlation between the kinetic sorption by FTIR and the SP concept. Copyright © 2007 John Wiley & Sons, Ltd.     

Mathematical approach for two component modeling of salep–starch mixtures using central composite rotatable design: Part II. Dynamic oscillatory shear properties and applicability of Cox–Merz rule

Dynamic shear rheological properties of salep–corn starch mixture (SCSM), salep–wheat starch mixture (SWSM) and salep–potato starch mixture (SPSM) samples were determined using a 2-factor-5-level Central Composite Rotatable Design (CCRD). Salep increased loss modulus (G″) values, and decreased loss tangent (tan δ) values of only SCSM; however, all starch types increased the storage (G′), loss (G″), complex (G^∗) modulus, complex viscosity (η^*) values and decreased tan δ values. At various salep and starch combination levels, a remarkable synergistic effect was observed in the dynamic shear properties. Potato starch exhibited completely different rheological performance in terms of G′, G″ and η^∗ values. Salep did not obey the Cox–Merz rule; however, a modified Cox–Merz rule was applicable for SCSM and SPSM samples. The ridge analysis revealed that maximum G′, G″, η^* and G^∗ values for the SCSM, SWSM and SPSM samples would occur at salep = 0.54% and 0.26%, respectively, and each starch type = 2.83%.     

Steady, Dynamic, Creep, and Recovery Analysis of Ice Cream Mixes Added with Different Concentrations of Xanthan Gum

Different xanthan gum concentrations (0–0.8 %) were tested, and the rheological properties of ice cream mixes were characterized as linear viscoelastic solids. Ostwald de Waele was successfully used to fit the steady shear data of ice cream mixes exhibiting a pseudoplastic flow (R ²?>?0.982). The samples with xanthan gum were characterized as strong gel-like macromolecular dispersions with G′ much greater than G″ but without a cross-point in the whole range of frequency applied. Cox–Merz rule was not applicable to the ice cream mixes. Steady and dynamic rheology of the ice cream mixes changed with increasing xanthan gum concentration. Besides, the four-component Burger model consisted of the association in series of the Maxwell model and the Kelvin–Voigt model was used to characterize the viscoelasticity. It was also found that the final percentage recovery parameters; J _SM, J _∞, J _KV, and %R (compliance of Maxwell spring and dashpot, Kelvin–Voigt element and R, respectively) of the ice cream mixes were dramatically changed by the xanthan gum concentration, increasing the internal structure parameters G ₀, G ₁, η ₀, and η ₁ (elastic moduli of Maxwell and Kelvin–Voigt springs and corresponding dashpot viscosities, respectively).     

A facile synthesis of polyaniline/polyethylene glycol/polyaniline terpolymers: preparation of electrospun conducting nanofibers by blending of the terpolymers with polycaprolactone

The water-soluble terpolymers were synthesized in two steps, containing esterification of polyethylene glycol (PEG) and 4-amino benzoic acid without protection of its amino group, then copolymerization of aniline from both end of amine-terminated PEG via an interfacial polymerization method. The chemical structure of triblock copolymers was determined by FTIR and ¹HNMR. The thermal behavior, morphology and electroactivity of terpolymers were also investigated by thermogravimetric analysis, field emission microscope (FESEM) and cyclic voltammetry (CV), respectively. Uniform nanofibers consisting of blends of (PANI)_n-b-PEG-b-(PANI)_n terpolymers and polycaprolactone (PCL) were prepared using electrospinning technique. The FESEM was also used to investigate the electrospun nanofibers produced from different molecular weight of PANI/PEG/PANI terpolymers and PCL (30/70). The CV measurements of blends confirmed the preparation of electroactive nanofibers. The presence of terpolymers enhanced the spinnability of solution and significantly reduced the bead formation. This novel system opens up new and interesting opportunities for applications such as electroactive scaffold for tissue engineering.     

The influence of retention hole and adhesive systems on the shear bond strengths of resin composite to amalgam

The aim of the study is to evaluate the influence of surface-treatment methods with and without the use of a retention hole on the shear bond strength of a resin composite adhered to amalgam using an adhesive system. Amalgam specimens were divided into six groups. Group 1 (Bur) specimens were roughened with a diamond bur, Group 2 (Al₂O₃) specimens were sandblasted with a 50?μm aluminum oxide powder, Group 3 (CoJet^®) specimens were sandblasted with 30?μm CoJet^® Sand, Group 4 (Bur?+?Rh) specimen surfaces were prepared with a retention hole 1?mm in diameter and 1?mm deep and roughened with a diamond bur, Group 5 (Al₂O₃?+?Rh) specimens were also prepared with a retention hole and sandblasted with 50?μm aluminum oxide powder, and Group 6 (CoJet^®?+?Rh) surfaces were prepared with a retention hole and sandblasted with 30?μm CoJet^® Sand. Resin composite cylinders were bonded onto the amalgam surfaces using Xeno^® IV, Optibond? All-In-One, Clearfil? SE Bond, Adper? Single Bond Plus, and Scotchbond? Multi-Purpose adhesive systems. In addition, silane (Monobond S) was used for Groups 5 and 6. The shear bond was determined and statistically analyzed using two-way analysis of variance and post hoc Tukey’s tests (p?≤?0.05). The surface treatment significantly affected the shear bond strengths of the adhesive systems. The shear bond strengths of Optibond? All-In-One (2.661?±?0.48?MPa) in Group 1 and Scotchbond Multi-Purpose (3.818?±?0.98) in Group 4 were significantly higher than those of the other adhesive systems. Silica coating of the amalgam surface significantly improved the shear bond strength of the resin composites. The addition of a retention hole on the amalgam affects the bonding strength of the composite adhesion.     

The effect of bulk-fill flowable composites on the fracture resistance and cuspal deflection of endodontically treated premolars

The aim of this study was to evaluate the effect of bulk-fill flowable composites on cuspal deflection and fracture resistance of endodontically treated teeth. Forty-two maxillary premolars were subjected to endodontic treatment followed by the preparation of mesioocclusodistal cavities. Teeth were divided into six groups according to restorative materials as follows: Group 1: Clearfil Majesty Flow and Clearfil Majesty Posterior; Group 2: Venus Bulk Fill and Clearfil Majesty Posterior; Group 3: Clearfil Majesty Posterior; Group 4: Vertise Flow and Clearfil Majesty Posterior; Group 5: SDR and Clearfil Majesty Posterior; and Group 6: x-tra base and Clearfil Majesty Posterior. A single-step self-etch adhesive (OptiBond All-in-One) was applied to all groups, except Group 4. The cavities were restored with a centripetal incremental insertion technique and flowable composites using a 2-mm-thick base material, except for Group 3. The distance between cusp tips was measured before and after the cavity preparations, after the restorations, and after thermal cyclus with a digital micrometer. After measuring, each tooth was subjected to compressive loading with a stainless steel ball (4 mm diameter) perpendicular to the occlusal surface with a crosshead speed of 1 mm/min, and mean loads necessary to fracture were recorded in Newtons. The data were statistically analyzed by Kruskal–Wallis test. No statistically significant differences were found between groups in fracture strength or cuspal deflections (p > 0.05). Bulk-fill flowable composite bases did not change the cuspal deflection or fracture resistance of endodontically treated teeth, compared with that of a conventional flowable base and conventional resin composite.     

Art and technology interactions in Islamic and Christian context: Historical approach to architectural globalization

Efficient interaction between art and technology enabled Islamic architecture to actively experience early globalization, but today's separation between these domains and technolo-gical hegemony have presented challenges to Islamic architecture. Accordingly, this research was aimed at illuminating art and technology interactions in Islamic architecture during early globalization when it flourished along with Christian architecture. To this end, logical reasoning and qualitative data analysis were performed in parallel on 12 chains of mostly worship-oriented artworks, such as mosques and churches. The results indicated that art and technology interactions in Islamic and Christian architecture were underlain by the same nature and sequential pattern of beginning from primitive technology and ending with innovative technology (art). The cultural and technological value of these architectural styles eventually crossed geographical boundaries. Therefore, the beneficial interactions between art and technology enabled Islamic and Christian architecture to participate in globalization through the conveyance of their value to other regions even as differences existed in the measures implemented for such transmission.     

A Hybrid-Similarity Exemplar Model for Predicting Distinctiveness Effects in Perceptual Old-New Recognition.

In 2 sets of experiments, the authors investigated the basis for old-item distinctiveness effects in perceptual recognition, whereby distinctive old items are recognized with higher probability than are typical old items. In Experiment 1, distinctive old items were defined as those lying in isolated regions of a continuous-dimension similarity space. In this case, any beneficial effects of distinctiveness were absent or small, regardless of the structure of the test list used to assess recognition memory. In Experiment 2, distinctive items were defined as those objects containing certain discrete, individuating features. In this case, large old-item distinctive effects were observed, with the nature of the effects being modulated by the structure of the test lists. A hybrid-similarity exemplar model, combining elements of continuous-dimension distance and discrete-feature matching, was used to account for these distinctiveness effects in the recognition data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)