Direct determination of phenolic compounds in Sicilian wines by liquid chromatography with PDA and MS detection

Phenolic compounds in Sicilian wines were directly detected using an HPLC with a PDA detector coupled on-line with a MS system equipped with Electrospray Ionisation (ESI) source operated in the negative-ion mode and a quadrupole mass analyzer. In this work, MS spectra were recorded at different voltage, to obtain structural elucidations in addition to molecular mass informations. The different response of the compounds identified has been also evaluated. MS characteristics of cis- and trans-piceid were determined on the basis of the response obtained with the ESI interface.     

Polymerization in magnetic field: XVIII. Influence of surfactant nature on the synthesis and thermal properties of poly(methyl methacrylate) and poly[(methyl methacrylate)‐co‐(epoxypropyl methacrylate)]

BACKGROUND: The possibility to use β‐cyclodextrin as biodegradable tensioactive and an electromagnetic field in order to improve the kinetic parameters of radical emulsion polymerization is of interest. Thus, the influence of different surfactants—sodium lauryl sulfate (SLS) and β‐cyclodextrin (CD)—on the pathway of emulsion polymerization of methyl methacrylate (MMA) and emulsion copolymerization of MMA with 2,3‐epoxypropyl methacrylate (GMA) performed with or without the presence of a continuous electromagnetic field (MF) was studied. RESULTS: The presence of the MF leads to a considerable increase of the conversion during the first part of the reaction if the classic surfactant (SLS) is used. The reactions performed without MF and with CD exhibit a decrease of the conversion and of the polymerization rate as compared with the variants using SLS. The swelling rate and the maximum degree of swelling vary with the surfactant nature and with the reaction conditions and MF presence. Data from thermogravimetry and differential scanning calorimetry evidence the dependences between the polymer characteristics and the preparation conditions. CONCLUSION: This research underlines the coupling possibilities of the influence of a MF—growth of the reaction rate and conversion explained through radical pairs mechanism—with a combination of the ‘cage’ effect and ‘conformational control’ afforded by CD. The presence of MF and CD during the syntheses leads to an increase of T_g and an increase of PMMA and P(MMA‐co‐GMA) thermal stability. Copyright © 2007 Society of Chemical Industry     

Structural modifications induced by recycling of polypropylene

The effect of numerous reprocessing cycles on transport properties of isotactic polypropylene (iPP) films was studied and related to the change of molecular weight and molecular weight distribution occurring during the recycling. Sorption curves of dichloromethane vapor in different samples of iPP were analyzed at 25°C to investigate the effect of structure modifications on the sorption mode. Moreover, gas permeability measurements were performed to evaluate the influence of reprocessing on the gas transport properties. The results obtained were attributed to modifications in the molecular structure of the polymer, evidenced from gel permeation chromatography (GPC), and to a different morphology of the films, as results from X-ray diffractograms and dynamic-mechanical thermal analysis (DMTA).     

Soft-Seeded Pomegranate (<Emphasis Type="Italic">Punica granatum</Emphasis> L.) Varieties: Preliminary Characterization and Quality Changes of Minimally Processed Arils During Storage

A preliminary characterization of two new soft-seeded pomegranate varieties (MR-100® and KINGDOM®) based on their main physico-chemical and nutritional parameters was reported. The two varieties showed significant differences (p ≤ 0.05) in polyphenols, anthocyanins and antioxidant activity. Kingdom pomegranate had higher polyphenols (2524.73 mg GAE/L), anthocyanins (752.49 mg C₃gE/L) and antioxidant activity (EC₅₀ 13.58 μL/mL) than MR-100 (1792.74 mg GAE/L, 141.29 mg C₃gE/L and EC₅₀ 47.53 μL/mL, respectively). Moreover, minimally processed arils of the two varieties were packaged in semipermeable and micro-perforated film at 5 °C, and the quality changes that occurred during storage condition (15 days) were investigated. During storage, Kingdom arils exhibited a better performance in terms of antioxidant activity, polyphenols and anthocyanin content with respect to MR-100. Furthermore, the packaging systems did not affect the estimated quality parameters for both varieties. Based on the sensory evaluation and microbial counts, both aril varieties reached, at 15-day storage, suitable values for commercial purpose.     

An IR molding system for direct shaping of thermoplastics

A new molding technique is proposed to directly mold small parts from thermoplastic pellets. A small molding machine was designed and fabricated: the mold consisted of a transparent glass and a metallic frame; an infrared (IR) lamp provided the heat for the pellet melting. Molding tests were carried out by using three commercial thermoplastics and two metallic molds. Molding time and IR lamp power were changed to extract a moldability window for each combination of material and metallic mold. In the best process conditions, a high quality of the samples was obtained in terms of mold filling and surface aesthetics. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

Toward multimodal notation for mathematics: Why and how

Notation is a tool of thought, recording and communicating concepts and activities related to a domain of knowledge. In the history of mathematical notation, written notation is usually considered. However, to be an effective thinking tool, notation must be properly perceived. Blind and partially sighted people run into difficulty in making, exploring and understanding mathematical concepts conceived for being represented in multi-dimensional space. In this paper, we capitalize on the multifaceted nature of digital symbols to define multimodal digital notation for graph structures that allows blind and partially sighted people to represent graph structures, reason about them and communicate their reasoning with sighted people as well as each other. As support tool for notation proposed we have designed a multimodal interactive system, in which haptic signals play a crucial role. An evolutionary prototype of the system has been developed and evaluated according to the star life cycle model.     

Identification by proteome analysis of muscle proteins in sea bream (<Emphasis Type="Italic">Sparus aurata</Emphasis>)

The present paper reported postmortem changes in muscle proteins on sea bream (Sparus aurata), during ice storage. The postmortem evolution of protein patterns in farmed sea bream was monitored by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimension electrophoresis (2DE). Matrix associated laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) was used for identification of proteins. Results of the bio-informatics analysis demonstrate that: (1) the normalized volume of skeletal alpha-actin and tropomyosin is not affected by the time of storage; (2) the normalized volumes of myosin light chain 3 and of major histocompatibility complex (MHC) class II beta1 increase; (3) the normalized volumes of Sec 13-like and parvalbumin significantly decrease.     

Direct electrospray ionization mass spectrometry quantitative analysis of sebacic and terephthalic acids in biodegradable polymers

A direct, rapid, and easy electrospray ionization mass spectrometry (ESI-MS) method to determine concentrations of sebacic acid (SA) and terephthalic acid (TA) residues in biodegradable copolymers was developed. Copolyester samples were synthesized from 1,4-butanediol and sebacic and terephthalic acids by melt polymerization. Extraction of monomers was performed in methanol. Their concentrations were determined by direct infusion ESI-MS, without chromatographic separation, using 1,12-dodecanedioic acid (DDA) as an internal standard. Calibration curves were obtained by plotting the ratio of the areas of the peaks relative to monomers and DDA standard as a function of their concentration ratio. We validated the method by determining the concentration of TA residue using both the ESI-MS protocol and high-performance liquid chromatography (HPLC) analysis with UV detection. The linearity range and the detection limit of this assay were 0.1-5.0 and 0.01 ppm for SA and 0.1-6.0 and 0.03 ppm for TA. This assay represents a useful alternative to conventional methods currently employed for acid quantification, resulting advantageous for its speed and high sensitivity.     

Closure systems and L-subalgebras

Let X be a set and ? a class of L-subsets of X. ? is a “closure system” if it is closed with respect to greatest lower bounds. If $\text{?}$ is an L-subset, then the g.l.b. $\text{}\text{?}$tf of {$\text{g ? ?|g??}$} is said to be generated by $\text{?}$. We examine closure systems of L-subalgebras and propose formulas for the L-subalgebra of a required type generated by a given L-subset.