Indirect Determination of MCPD Fatty Acid Esters in Lipid Fractions of Commercially Available Infant Formulas for the Assessment of Infants’ Health Risk

Food Analytical Methods - MCPD esters are intensively investigated food lipid contaminants for over a decade. Concern related to their presence in various types of food products is related to the...     

Optimization of the electrospinning processing‐window to fabricate nanostructured PE‐b‐PEO and hybrid PE‐b‐PEO/EBBA fibers

An electrospinning technique is used to obtain poly(ethylene‐b‐ethylene oxide) block copolymer (PE‐b‐PEO) fibers. Optimization of the electrospinning processing‐window is carried out by varying the concentration of the block copolymer solution and playing with three different electrospinning parameters, applied voltage, solvent and block copolymer solution flow rate. The influence of the concentration of the block copolymer solution over the length and diameter of the fibers is mainly studied and results indicate that the optimum conditions to fabricate PE‐b‐PEO block copolymer fibers are concentrations between 45 and 47 wt% of PE‐b‐PEO block copolymer and chloroform/DMF mixture ratio of 4:1 and 5:1. Moreover, low solvent and block copolymer solution flow rates led to the longest and widest fibers. Hybrid fibers are also fabricated modifying PE‐b‐PEO block copolymer fibers with low molecular weight N‐(4‐ethoxybenzylidene)?4‐butylaniline (EBBA) nematic liquid crystal using coaxial electrospinning technique. The morphology of the fabricated fibers is investigated from micro to nanoscale. Atomic force microscopy (AFM) results show self‐organization of investigated PE‐b‐PEO and hybrid PE‐b‐PEO/EBBA fibers on the nanometric scale, which make them interesting from the point of view of novel applications as template materials. POLYM. ENG. SCI., 57:1157–1167, 2017. © 2017 Society of Plastics Engineers     

Liquid-crystalline phases formed by symmetrical azines with different terminal chains: Thermal,optical and electrical study

One series of symmetrical azine-type liquid crystals were synthesized and their chemical structure identified by FTIR, NMR, high resolution mass spectrometry-electro spray ionization (MS-ESI) and elemental analysis. The absorption (UV–vis), photoluminescence (PL) and thermoluminescence (TL) features of the compounds are documented. X-ray diffraction was employed to evaluate their phase transitional behaviour. Their mesomorphic properties were investigated by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). Terminal groups of the liquid crystals had an effect on their mesomorphic properties. Azine with alkoxysemiperfluorinated end-groups (A1) exhibited smectic C (SmC) phase, whereas azine with octadecyloxy end chains (A3) showed SmC and SmA phases. Azine with 5″-octyl-2,2′:5′,2″-terthiophene groups (A2) exhibited only nematic phase. Different types of N and SmC textures were found and investigated by POM technique. Azine with thiophene groups (A2) has an absorption band about 138 nm batochromically shifted compared to the analogous band of other compounds. The lowest optical band gap value (2.34 eV) was detected for A2. Azines emitted violet or green light. The thermoluminescence emission of azines occurred at about 390–440 nm wavelengths. Current–voltage measurements were performed on ITO/compound/Alq₃/Al and ITO/TiO₂/compound/Alq₃/Al devices before and after light irradiation. To prepare TiO₂ layer, sol–gel technique was applied.     

A study of thermal,optical and electrical properties of new branched triphenylamine-based polyazomethines

A series of branched aromatic polyazomethines have been obtained by high temperature solution polycondensation of 4,4′,4″-triformyltriphenylamine with 3,3′-dimethoxybenzidine with different feed molar ratio. For three polymers additional condensation of chain end groups with monofunctional monomers such as 4-formyltriphenylamine or 2-naphthylamine was carried out. Moreover, two model compounds were prepared and investigated for comparison with branched polymers. The structures of polymers and models were characterized by means FTIR, ¹H, ¹³C NMR spectroscopy, elemental analysis and gel permeation chromatography (GPC). UV–vis properties of the thin films of the polymers and compounds were investigated on the glass substrate. Eg of the branched polymers was found about 2.47 eV. UV–vis and FTIR spectroscopy for iodine doped compounds were investigated. Doping decreased the value of Eg of the branched polyazomethines to about 1.71 eV. Refractive index (n) for branched polyazomethines was found about 1.97, while for the doped compounds was a little higher (～2.48). Absorption (UV–vis) properties of the doped with iodine branched imines were investigated additionally after heating in different temperatures from 50 to 200 °C. Intensity of photoluminescence of branched imines in relation to 9,10-diphenylanthracene was found in the range 0.2–1.0% and 2.7–43.7% in dependence on the excitation wavelengths. Current–voltage (I–V) measurements were performed on ITO/TiO₂/polymer/Al, ITO/polymer/Alq₃/Al and ITO/TiO₂/polymer/Alq₃/Al devices in the dark and during irradiation with light (under illumination 1000 W/m²). The sol–gel technique was applied to prepared TiO₂ layer. TiO₂ layers and devices were investigated by Atomic Force Microscopy (AFM). Moreover, properties of these branched polymers were compared with the linear polyazomethine based on 3,3′-dimethoxybenzidine and 4,4′-diformyltriphenylamine.     

Non-normal distribution of the top-of-atmosphere satellite optical measurements over calibration sites

This paper studies the distribution associated with the measurement of the satellite-derived top-of-atmosphere (TOA) reflectance on a pixel-to-pixel level, within a defined spatial region of interest (ROI) within a vicarious calibration target site. The study analyses the effects of the atmosphere and surface reflectance distribution spatial shape. The analysis shows that some of the contributing effects are inherently nonlinear, so produce non-normal distributions. For these non-normal distributions, the use of the mean and standard deviation alone does not allow sufficient parameterization of the distribution to capture all the information associated with the ROI reflectance measurement. Therefore, additional information concerning the distribution is required to provide a full site reflectance characterization. This additional information can be useful in establishing the sources of change in the distribution and ultimately improve the site radiometric characterization, particularly for long-term monitoring. In this study, Landsat-8 (L8) Operational Land Imager (OLI) measurements over the CEOS Libya-4 Pseudo Invariant Calibration Site (PICS) are used as a demonstration.     

‘Dealing with My Emails’: Latent user needs in email management.

Email is a communication channel that provides a number of benefits. It can be stored, retrieved and forwarded. It also allows a recipient to choose when to uptake communication and how to pace it. However, email also incurs one prevalent cost: the feeling of email overload. One of the reasons leading to that feeling lays in the fact that current email clients do not provide an inbox structure that facilitates email prioritization, information structuring and work-flow management. The goal of this study was to understand the latent user needs regarding handling emails. We identified six such needs: three pertaining to email organization (email annotation, reliable structure and no urgency to classify) and three related to email retrieval (informative overview, flexible sorting and efficient search). We further investigated the dominance, importance and dependencies between these needs. The results were then discussed and implications for future inbox design were proposed.