Toughening of poly(lactide) using polyethylene glycol methyl ether acrylate: Reactive versus physical blending

To design high‐performance poly(lactide)‐based materials (PLA‐based) with improved toughness, two approaches based on the reactive extrusion (REx) process are investigated and compared in the present study. The first approach relies upon a two‐step procedure using a REx‐polymerized poly(ethylene glycol) methyl ether acrylate, i.e., poly(AcrylPEG), as a highly‐branched and compatible impact modifier for PLA. The free‐radical polymerization proves to be very efficient with a peroxide initiator concentration of 1 wt%. The as‐produced poly(AcrylPEG) is then melt‐blended with PLA by extrusion. The resulting materials exhibit largely increase impact resistance (ca. 35 kJ/m²) in presence of 20 wt% poly(AcrylPEG) in comparison with neat PLA (2.7 kJ/m²), while moderate ductility (tensile elongation at break <40%) and limited plasticization effect are observed. The second “one‐step” approach consists in in situ grafting of AcrylPEG onto PLA backbone via a one‐stage REx. The resulting materials exhibit substantially improved impact resistance (ca. 102 kJ/m²) for AcrylPEG loading of 20 wt%, high ductility (tensile elongation at break of ca. 150%) and efficient plasticization. A detailed characterization of the morphology of the materials has been performed using PF‐QNM‐AFM to better elucidate the structure‐property relationships. POLYM. ENG. SCI., 55:1408–1419, 2015. © 2015 Society of Plastics Engineers     

Dietary Lipid Intake only Partially Influences Variance in Serum Phospholipid Fatty Acid Composition in Adolescents: Impact of Other Dietary Factors

The present study aimed to assess the correlation between food and fatty acid (FA) intake and the serum phospholipid (PL) FA status in European adolescents and explored the percentage of variation in serum PL FA that could be attributed to dietary habits. Participants included 528 adolescents recruited in the HELENA Study. Dietary intake was assessed by two, self-administered, non-consecutive 24-h recalls. PL FA concentrations were measured in fasting venous serum samples. Reduced rank regressions were applied to examine the combined effect of food intakes. Results indicated that the variance in serum PL FA in adolescents, that could be explained by diet varied from 7.0 % for MUFA to 14.2 % for n-3FA. The variance in the long-chain n-3FA was mainly explained by fish intake but also by coffee and tea consumption. In conclusion this study indicated that dietary intake influences the serum PL FA status to a limited amount but that also other factors interfere. However, dietary intake is important as it is among those factors that could be modified. Furthermore, the results suggest that the overall dietary habits should be considered instead of only the consumption of single foods or nutrients, as the medium of the food or concomitant intake of foods and nutrients might interact and as such influence absorption or metabolism.     

The synthesis and characterization of near-infrared absorbing,electrochromic polyimides containing a dinuclear ruthenium complex in the polymer mainchain

A redox-active, near-infrared absorbing dinuclear ruthenium complex was incorporated into the mainchain of polyimides using a two-stage polymerization method. The polyimides show high thermal stability with a decomposition temperature range from 172 to 248 °C and glass transition temperature of 97–180 °C, depending on the dianhydride monomer used. The polyimides are redox active, electrochromic at 1600 nm with the ruthenium complex being in the mixed-valence state and fluorescent at 790 nm.     

Mechanical and interfacial properties of wood and bio-based thermoplastic composite

The aim of this investigation was to study a new family of wood polymer composites with thermoplastic elastomer matrix (pebax® copolymers) instead of commonly used WPC matrices. These copolymers are polyether-b-amide thermoplastic elastomers which present an important elongation at break and a melting point below 200 °C to prevent wood fibers degradation during processing. Moreover these polymers are synthesized from renewable resources and they present a hydrophilic character which allow them to interact with wood fibers. We have used two pebax® grade with different hardness and three types of wood fibers, so the influence of the matrix and wood fibers characteristics were evaluated. Composites were produced using a laboratory-size twin screw extruder to obtain composite pellets prior to injection moulding into tensile test samples. We have evaluated fibers/matrix interaction by differential scanning calorimetry (DSC), infrared spectroscopy (IRTF) and scanning electron microscopy (SEM). Then, the mechanical properties, through tensile test, were assessed. We also observed fibers dispersion into the matrix by tomography X. DSC, IRTF and SEM measurements confirmed the presence of strong interface interactions between polymer and wood. These interactions lead to good mechanical properties of the composites with a reinforcement effect of wood fibers due also to a good dispersion of fibers into the matrix without agglomerate.     

Toxigenic status of Staphylococcus aureus isolated from bovine raw milk and Minas frescal cheese in Brazil

A group of 291 Staphylococcus aureus isolates from mastitic cow's milk (n = 125), bulk tank milk (n = 96), and Minas frescal cheese (n = 70) were screened for staphylococcal enterotoxin (SE) genes (sea, seb, sec, sed, see, seg, seh, sei, selj, and sell) and for the tst-1 gene encoding staphylococcal toxic shock syndrome toxin 1 by PCR assay. A total of 109 (37.5%) of the isolates were positive for at least one of these 11 genes, and 23 distinct genotypes of toxin genes were observed. Of the S. aureus isolates bearing SE genes, 17 (13.6%) were from mastitic cow's milk, 41 (41.7%) were from bulk tank milk, and 51 (72.9%) were from Minas frescal cheese. The occurrence of exclusively more recently described SE genes (seg through sell) was considerably higher (87 of 109 PCR-positive strains) than that of classical SE genes (sea through see, 15 strains). The SE genes most commonly detected were seg and sei; they were found alone or in different combinations with other toxin genes, but in 60.8% of the cases they were codetected. No strain possessed see. The tst-1 gene was found in eight isolates but none from mastitic cow's milk. Macrorestriction analysis of chromosomal DNA from 89 S. aureus isolates positive for SE gene(s) was conducted with the enzyme SmaI. Fifty-five distinct pulsed-field gel electrophoresis patterns were found, demonstrating a lack of predominance of any specific clone. A second enzyme, Apa I, used for some isolates was less discriminating than Sma I. The high genotype diversity of potential toxigenic S. aureus strains found in this study, especially from Minas frescal cheese, suggests various sources of contamination. Efforts from the entire production chain are required to improve consumer safety.     

Preliminary data on the presence of mycotoxins (ochratoxin A, citrinin and aflatoxin B1) in black table olives "Greek style" of Moroccan origin

Many mould strains, in particular Aspergillus and/or Penicillium, are able to develop on olive and produce ochratoxin A (OTA) and/or citrinin (CIT) and/or aflatoxin B (AFB) after harvest, during drying and storage of olives. The development of fungi on olives is responsible for the reduction of nutritional quality of olive because they can disturb the synthesis of the fatty acids. OTA, CIT and AFB are particularly dangerous for health, inducing cancer of urinary tracts or liver carcinoma. In this study, ten olive samples bought at retailer and at supermarket in Morocco were analyzed for their OTA, CIT and AFB contents. These three mycotoxins were extracted simultaneously by a method based on solvent partition validated in-house, then separated by HPLC coupled to a fluorescence detector. All olive samples contain OTA ranging from LOQ to 1.02 microg/kg. Respectively, 50 and 25% from retailer and supermarket samples were contaminated by more than 0.65 microg/kg. In addition, 80% of olive samples contained CIT above LOD, and 100% of olive tested contained AFB above 0.5 microg/kg. As simultaneous presence of these toxins increases toxic risks, it is thus essential to have a good control of the conservation of olives after harvest.     

Synthesis and characterization of poly(dipropargyloxynaphtoates) containing polar Azo dyes

Summary In order to study the relationships between the chemical structures of polymer main chains and second order nonlinear optical properties, novel polymers with hexa-2,4-diynylene-1,6-dioxynaphthoate as a main chain and common azo dyes (Disperse Red 1 and 13) in the side chains, were synthesized and characterized. The polymers were soluble in common organic solvents such as chloroform, dimethylformamide, N-methylpyrrolidone, etc, and gave films with excellent optical quality by spin coating. Apparent orientation parameters of around 0.25 were observed by the absorption decrease by Corona poling. The steric effect of chlorine atom of the dye on poling was not observed. On heating at 100 °C after poling the order parameters did not return to zero but reached a constant. It is thought that some of the chromophores remain orientated permanently.     

Fabrication of a novel nanocomposite SiO2–H3BO3–V2O5–Al2O3 via melt-quenching technique: structural and surface morphological characteristics for carbon dioxide gas sensing applications

Journal of Materials Science: Materials in Electronics - Herein, a novel nanocomposite 38SiO2–33H3BO3–25V2O5–4Al2O3 (SHV4A) was successfully fabricated using a melt-quenching...     

Automatic breast cancer detection based on optimized neural network using whale optimization algorithm

Breast cancer is the second deadliest type of cancer. Early detection of breast cancer can considerably improve the effectiveness of treatment. A significant early sign of breast cancer is the mass. However, separating the cancerous masses from the normal portions of the breast tissue is usually a challenge for radiologists. Recently, because of the availability of high‐accuracy computing, computer‐aided detection systems based on image processing have become capable of accurately diagnosing the various types of cancers. The main purpose of this study is to utilize a powerful image segmentation method for the diagnosis of cancerous regions through mammography, based on a new configuration of the multilayer perceptron (MLP) neural network. The most popular method for minimizing the errors in an MLP neural network is backpropagation. However, this method has certain drawbacks, such as a low convergence speed and becoming trapped at the local minimum. In this study, a new training algorithm based on the whale optimization algorithm is proposed for the MLP network. This algorithm is capable of solving various problems toward the current algorithms for the analyzed systems. The proposed method is validated on the Mammographic Image Analysis Society database, which contains 322 digitized mammography images, and the Digital Database for Screening Mammography, which contains approximately 2500 digitized mammography images. To assess the detection performance of the proposed system, the correct detection rate, percentage of identification with false acceptance, and percentage of identification with false rejection were evaluated and compared using various methods. The results indicate that the proposed method is highly efficient and yields significantly better accuracy compared with other methods.     

Modelling Intelligent Driving Behaviour Using Machine Learning

In vehicular systems, driving is considered to be the most complex task, involving many aspects of external sensory skills as well as cognitive intelligence. External skills include the estimation of distance and speed, time perception, visual and auditory perception, attention, the capability to drive safely and action-reaction time. Cognitive intelligence works as an internal mechanism that manages and holds the overall driver’s intelligent system.These cognitive capacities constitute the frontiers for generating adaptive behaviour for dynamic environments. The parameters for understanding intelligent behaviour are knowledge, reasoning, decision making, habit and cognitive skill. Modelling intelligent behaviour reveals that many of these parameters operate simultaneously to enable drivers to react to current situations. Environmental changes prompt the parameter values to change, a process which continues unless and until all processes are completed. This paper model intelligent behaviour by using a ‘driver behaviour model’ to obtain accurate intelligent driving behaviour patterns. This model works on layering patterns in which hierarchy and coherence are maintained to transfer the data with accuracy from one module to another. These patterns constitute the outcome of different modules that collaborate to generate appropriate values. In this case, accurate patterns were acquired using ANN static and dynamic non-linear autoregressive approach was used and for further accuracy validation, time-series dynamic backpropagation artificial neural network, multilayer perceptron and random sub-space on real-world data were also applied.