High resolution melting analysis for quantitative detection of bovine milk in pure water buffalo mozzarella and other buffalo dairy products

Identification of buffalo dairy products has become an important issue to ascertain product quality, consumer rights and absence of food-borne allergic reactions. A polymerase chain reaction (PCR) followed by a high resolution melting (HRM) analysis was developed and applied for species specific detection of bovine milk in nine different commercial buffalo dairy products. A specific buffalo 12S rRNA and a bovine d-loop primer pair, targeting the mitochondrial genome, were employed in a duplex PCR assay. The analysis developed was found capable of identifying the presence of bovine milk down to 1% in commercial buffalo milk products and also of quantifying the ratio of bovine into buffalo milk. HRM was proven to be a fast and accurate technique for a routine authentication testing of mozzarella and other buffalo milk products.     

Failure Analysis of a Cast Mn-Bronze Propeller

The investigation of a failure of a cast manganese bronze propeller, fractured after a short service period (~4–5 months), was conducted. Chemical analysis, visual inspection, optical microscopy, fractographic evaluation, SEM/EDS analysis, and hardness testing were used as the principal analytical tools for the failure investigation. The findings suggest that the failure occurred due to fatigue mechanism under low stress conditions. The non-conformities detected in material chemical composition, as well as the presence of internal and surface flaws could be considered as the main contributors of the premature failure of the propeller.     

Barcode High Resolution Melting (Bar-HRM) analysis for detection and quantification of PDO “Fava Santorinis” (Lathyrus clymenum) adulterants

Legumes considered as one of the most important crops worldwide. Due to high price as a PDO product, commercial products of “Fava Santorinis” are often subjected to adulterations from other legume products coming from other Lathyrus or Vicia and Pisum species. Using plant DNA barcoding regions (trnL and rpoC) coupled with High Resolution Melting (Bar-HRM) we have developed a method allowing us to detect and authenticate PDO “Fava Santorinis”. Bar-HRM proved to be a very sensitive tool able to genotype Lathyrus and its closed relative species and to detect admixtures, being sensitive enough to as low as 1:100 of non-“Fava Santorinis” in “Fava Santorinis” commercial products. In conclusion, Bar-HRM analysis can be a faster, with higher resolution and cost effectiveness alternative method to authenticate PDO “Fava Santorinis” and to quantitatively detect adulterations in “Fava Santorinis” with other relative commercial “Fava” food products.     

Polyurethanes from 4,4′‐diphenylmethane diisocyanate and poly(ethylene glycol)s. II. Crystallographic data,heats of melting and crystallization,thermal stability,crystallinity and density

Wide‐angle X‐ray scattering analysis, heats of melting, crystallization and re‐melting, thermogravimetric analysis and density measurements have been used to study the crystallographic data and degree of crystallinity of linear polyurethanes (PUs) prepared by the polymerization of 4,4′‐diphenylmethane diisocyanate (MDI) with poly(ethylene glycol)s (PEGs) of various number‐average molecular weights (M_ns) (106, 200, 400, 1000, 2000 and 4000 g mol^?1) in equivalent molar ratios. The crystallinities of polyurethanes PU1000 to PU4000 are shown to be due to the polyoxyethylene segments of the PEGs, while PU400 and PU200 appeared to be amorphous. However, PU106, similarly prepared from diethylene glycol (PEG106), is highly crystalline with a different crystal structure. Thermogravimetric analysis of PU106, PU400 and PU1000 exhibited high thermal stabilities up to 260 °C for these materials under the conditions of measurement (10 °C min^?1). The heat of melting for the 100 % crystalline structure of PU106 has been indirectly obtained. Copyright © 2004 Society of Chemical Industry     

Extrusion of self-reinforced thermoplastic composites illustrated by high density polyethylene

A method is described for solid state coextrusion of self-reinforced and transparent composites for high density polyethylene composed of core and sheath components. The high density polyethylenes are coextruded below their melting points. The cocylindrical composites have a high tensile modulus and strength, a high orientation for both core and sheath components and possess considerable resistance to core/sheath separation. This resistance to pull-out is due to compressive and radial stresses developed during the composite coextrusion and not to bonding by epitaxial crystallization.     

Identification of lactic acid bacteria isolated from poultry carcasses by high-resolution melting (HRM) analysis

Lactic acid bacteria (LAB) are a complex group of Gram-positive bacteria belonging to different genera with common morphological, metabolic and physiological characteristics. Their classification was initially based on biochemical methods, but nowadays molecular methods are usually applied for the identification of LAB. Herein, real-time PCR assay coupled with high-resolution melting (HRM) analysis was developed for identifying and distinguishing LAB isolates coming from poultry carcasses. The 16S rRNA gene from these isolates was amplified using primers that annealed to conserved regions. The melting curve analysis of the amplicons classified all isolates into ten LAB species and generated ten distinct HRM curve profiles. The results from HRM analysis were compared to those produced by API 50 CH biochemical microkits and ribosomal DNA sequencing, suggesting the superiority of HRM against API. In conclusion, HRM was proven to be a fast, reliable and cost-effective method for identification of LAB isolates. HRM analysis could be used in order to reduce the time needed for the identification assay and the cost of sequencing the entire group of LAB isolates. The melting profile of known LAB species could be used as a reference for the rapid identification of unknown LAB isolates without the need of sequencing.     

Mechanical behaviour and microstructure of heat-treated Cu–Ni–Si alloy

ABSTRACT

Cu–Ni–Si alloys exhibit a good combination of strength and electrical conductivity and may be a potential candidate for utilisation in electrotechnical applications. In this work, the mechanical behaviour and its relation to the microstructure of a Cu–Ni–Si alloy, subjected to different solution heat treatment cycles, were investigated. Tensile, bend and hardness testing, in addition to Optical and Scanning Electron Microscopy, were employed, as the main analytical techniques, in the context of the present investigation.

This paper is part of a Thematic Issue on Copper and its Alloys.     

The effect of initial morphology on the mechanical properties of ultra-high molecular weight polyethylene

Studies of the physical and mechanical properties of melt crystallized ultra-high molecular weight polyethylene morphologies from melts with different thermal histories indicate that their properties depend on the degree of fusion of the powder particles during their processing and can be enhanced by heating the polymer above 220°C. The degree of cohesion of the powder particles and their initial morphology also have a significant effect on the deformability of the polymer in the solid state forming methods used to prepare high modulus and strength products.