Prediction of density,porosity and hardness in aluminum–copper-based composite materials using artificial neural network

The potential of using feed forward backpropagation neural network in prediction of some physical properties and hardness of aluminium–copper/silicon carbide composites synthesized by compocasting method has been studied in the present work. Two input vectors were used in the construction of proposed network; namely weight percentage of the copper and volume fraction of the reinforced particles. Density, porosity and hardness were the three outputs developed from the proposed network. Effects of addition of copper as alloying element and silicon carbide as reinforcement particles to Al–4 wt.% Mg metal matrix have been investigated by using artificial neural networks. The maximum absolute relative error for predicted values does not exceed 5.99%. Therefore, by using ANN outputs, satisfactory results can be estimated rather than measured and hence reduce testing time and cost.     

Polysaccharides from prickly pear peel and nopals of Opuntia ficus‐indica: extraction,characterization and polyelectrolyte behaviour

The extraction at natural pH of carbohydrate polymers from Opuntia ficus‐indica and their physicochemical characterization are reported. Polysaccharides extracted from nopal pulp, nopal peel and pear peel, are denoted NPU, NPE and PPE respectively. For comparison, extraction of the peel of fruit has also been carried out using the conventional acid process generally employed for pectin (PPI). The sugar composition indicates that all the polysaccharides obtained contain anionic moieties, galacturonic acid residues, from 10% for NPU to about 50% for those extracted from peels, the composition of which is typical of pectin. The macromolecular features of these compounds have been characterized by size‐exclusion chromatography coupled with multi‐angle laser light‐scattering detection (SEC–MALLS) and by capillary viscometry, leading to information on conformation and size dimension of macromolecules in dilute aqueous solutions. Our findings show that the polysaccharides from nopals have a random coil structure, whereas those from fruit peel exist as a compact sphere which is assumed to be due to a branched structure. The polyelectrolyte character related to the presence of fixed charges on the chain has been investigated as a function of pH and ionic strength. The conformational change from a compact form in acidic medium to an expanded one takes place in the pH range 4–6. A strong tendency to form aggregates in acidic medium is evidenced by SEC–MALLS. The differences observed in the solution behaviour of the studied polysaccharides are discussed in terms of intra‐ and inter‐macromolecular interactions. © 2001 Society of Chemical Industry     

A new case of false aneurysm of the superior mesenteric artery

The sensitizing capacity of brewer's yeast (Saccharomyces cerevisiae) was studied with the skin prick test method in 449 subjects, including 226 atopic dermatitis (AD) patients, 50 patients with allergic rhinitis (AR) and/or asthma (A), and 173 nonatopic controls. A positive SPT reaction (> or = + +) was seen in 94% of patients with severe AD, in 76% with moderate AD, and in 25% with mild AD or no history of AD. Patients with AR and/or A and nonatopic controls displayed a positive reaction in only 8 and 2% of cases, respectively. There was also a parallel skin prick test reactivity with other yeasts including Pityrosporum ovale and Candida albicans, suggesting cross-reactivity. Parallel skin reactivity was observed also with molds and animal dander but not with pollen or house-dust mite. A significant correlation was also found between total serum IgE level and skin prick test (SPT) results with S. cerevisiae.     

UHPLC-ESI-MS/MS Quantification of Relevant Substrates and Metabolites of the Kynurenine Pathway Present in Serum and Peritoneal Fluid from Gastric Cancer Patients—Method Development and Validation

Metabolites and enzymes involved in the kynurenine pathway (KP) are highly promising targets for cancer treatment, including gastrointestinal tract diseases. Thus, accurate quantification of these compounds in body fluids becomes increasingly important. The aim of this study was the development and validation of the UHPLC-ESI-MS/MS methods for targeted quantification of biologically important KP substrates (tryptophan and nicotinamide) and metabolites(kynurenines) in samples of serum and peritoneal fluid from gastric cancer patients. The serum samples were simply pretreated with trichloroacetic acid to precipitate proteins. The peritoneal fluid was purified by solid-phase extraction before analysis. Validation was carried out for both matrices independently. Analysis of the samples from gastric cancer patients showed different accumulations of tryptophan and its metabolites in different biofluids of the same patient. The protocols will be used for the evaluation of tryptophan and kynurenines in blood and peritoneal fluid to determine correlation with the clinicopathological status of gastric cancer or the disease’s prognosis.     

Aspects for untangling cross‐layer design and policy support

Programming language concepts have inspired some networking design decisions. For example, concepts such as object encapsulation and interface invocation have been borrowed, at the time of their adoption, from an already well established object oriented programming paradigm. The authors suggest in this paper that it may be time again to revisit emerging software engineering programming paradigms to learn from them. More specifically, this paper discusses the practical tangling problem, embedded in conventional layer‐coupling (linking) network software design and highlighted by recent research proposals for cross layer design. The adopted solution is based on the aspect‐oriented programming paradigm. We show its programming efficiency, limitations and role in the seamless enforcement of multiple policy scenarios while emphasizing little design changes. Copyright © 2012 John Wiley & Sons, Ltd.     

Differential detection of small pelagic fish in Tunisian canned products by PCR-RFLP: An efficient tool to control the label information

Correct identification of fish species including their origin requires a compilation of recognized material to verify the conformity of the product with the labelling requirement. Sardine is among the internationally disputed example of species identification conflicts, with the lack of genetic reference material at the Southern part of the Mediterranean. Therefore a method was developed to discriminate between Tunisian small pelagic fish: Sardina pilchardus, Sardinella aurita and Engraulis encrasicolus. DNA extraction from fresh fish and from 12 canned sardine and 2 anchovy-type products, was followed by a PCR method that specifically amplifies a 252 bp fragment of the cytochrome b gene. The new sequences which were deposited in the NCBI GenBank, were searched against a nucleotide sequence database (GenBank) and phylogenetically analyzed with the MEGA software. Multiple alignments of 3 analyzed reference samples belonging to Clupeomorpha species was performed versus the canned samples. Low intraspecific variability was observed for canned anchovy and sardine (<0.05), whereas mean interspecific variability was 0.23. A phylogenetic tree was constructed, and the calculated bootstrap values (BP, 71-100%) were used as indicators of the correct assignment of unknown canned samples to reference species. Postamplification digestion with HaeIII and ALuI restriction enzymes, yielded specific profiles that enabled anchovy to be distinguished from either of the sardine species. This PCR-RFLP was found to be reliable for species identification of canned fish products.     

Elicitation of a reference process model for tool-based micro technologies for planning and controlling purposes and user support

The production of moulded micro components including design, manufacture and quality control is a highly integrated process. A lot of experts, machines, tools, etc. should be deployed meaningfully along this process. The process chain was never written down in detail or as a whole so that new products could be developed on this basis. All developments hitherto have been carried out partly intuitive and partly based on area-specific sub process chains. For an efficient and effective planning and controlling and user support during future tool-based micro product engineering processes, the authors propose a corresponding reference process model. For this purpose, implicit process knowledge must be retrieved from expert’s minds to consider area-specific sub-process chains. For implementation of the reference process model, the Integrated Product Engineering Model (iPeM) will be used.     

Epidemiology and antibiotic resistance of Salmonella enterica Serovar Kentucky isolates from Tunisia: The new emergent multi-drug resistant serotype

Since 2002, the emergence of multidrug resistant Salmonella enterica serovar Kentucky (S. Kentucky) and the associated salmonellosis with treatment failure were declared in different parts of the world and were in most of the case contracted during travels to Northeast and Eastern Africa. In the present work, we reported an epidemiological study of S. Kentucky isolated from different environmental and clinical origins in Tunisia, using Pulsed-field gel electrophoresis (PFGE); Enterobacterial Repetitive Intergenic Consensus (ERIC-2) fingerprinting; Plasmid profiling; and antibiotic resistance profiles. ERIC-2 fingerprinting allowed the differentiation of 14 different patterns versus only 4 pulsotypes. Besides, a high proportion of strains were found to be nontypeable by XbaI-PFGE and/or by plasmid profiling (plasmid-free strains). The antibiotic resistance was mainly detected against streptomycin (80.7%), sulfonamides (42.1%) and tetracycline (15.7%). Furthermore, two avian strains were shown to be resistant to trimethoprim–sulfamethoxazole and three clinical strains have demonstrated multidrug-resistant phenotypes (against 5 to 10 antibiotics) and all of them exhibited resistance against nalidixic acid, ciprofloxacin, ofloxacin and tetracycline.ERIC-2 PCR was found to be the most discriminative. However, combination of the three typing methods offer a better mean for differentiating S. Kentucky isolates, monitoring the multiresistant types and determination of their origin.     

Determination of phenolic and other polar compounds in flaxseed oil using liquid chromatography coupled with time-of-flight mass spectrometry

A new method based on high-performance liquid chromatography coupled with electrospray ionisation time-of-flight-mass spectrometry (HPLC–ESI–TOF (MS)) has been used to analyse phenolic compounds in flaxseed oil. Some phenolic compounds such as secoisolariciresnol, ferulic acid and its methyl ester, coumaric acid methyl ester, diphyllin, pinoresinol, matairesinol, p-hydroxybenzoic acid, vanillin and vanillic acid have been detected from flaxseed oil. The quantification of these compounds in three varieties of flaxseed oils was carried out using their commercial standards. The efficiency, rapidity and high resolution of HPLC coupled to the sensitivity, selectivity, mass accuracy and true isotopic pattern from TOF (MS) have revealed an enormous separation potential allowing the determination of a broad series of phenolic and other polar compounds present in flaxseed oil for the first time.     

Development of composite materials reinforced with flat-knitted spacer fabrics

Flat-knitting technology has recently known spectacular developments with the advent of 3D spacer fabrics used as reinforcements of sandwich composites thanks to their improved mechanical properties. At present, studies dealing with the development and the characterization of these composites are quite rare .This work deals with the development of 3D-knitted composite using cotton yarn and unsaturated polyester resin. The aim of this work is to evaluate the utility of a natural reinforcement material in a technical use and assess the impact of fabric cross-link shape on composite mechanical performances. U- and V-shaped 3D spacer fabrics were produced and used to develop composite structures. These structures were characterized by flexion and flat compression tests. Results showed that composites reinforced with U spacer fabric have the best compression resistance whereas the best flexural properties were obtained with V-shaped fabric connection. The developed structures present competitive solution for light weight composites such as solar panels, blades of wind turbines, and sound absorbers.