Development and validation of a new LC–MS/MS method for the simultaneous determination of six major ergot alkaloids and their corresponding epimers. Application to some food and feed commodities

A liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed and validated for the simultaneous determination of six major ergot alkaloids, ergometrine, ergosine, ergotamine, ergocornine, ergokryptine and ergocristine, as well as their corresponding epimers in food and feed samples. The method involves extraction under alkaline conditions and subsequent clean-up by applying a simple and rapid liquid–liquid partitioning procedure prior to LC–MS/MS analysis. Evaluation of the method revealed good linearity, accuracy and precision. The limits of quantification varied from 0.1 to 1 μg/kg depending on the analyte and matrix. The average extraction and clean-up recoveries in different matrices were between 45 (only for ergometrine in biscuit) and 90%. The uncertainty associated with the analytical method was not higher than 51% and 30%, at concentration levels of 2.5 and 150 μg/kg respectively. Analyte epimerization proved to be minimal during the analytical procedure. The method has been successfully applied to the determination of ergot alkaloids in some Belgian food and feed commodities. Ergot alkaloids were found in 104 out of 122 samples investigated. Ergosine was the most frequently occurring alkaloid, while the highest levels were observed for ergotamine, ergocristine or ergosine, depending on the product type. The total alkaloid content in positive samples varied from 1 to 1145 μg/kg.     

Isolation of adipophilin and butyrophilin from bovine milk and characterization of a cDNA encoding adipophilin

The milk fat globule membrane-associated proteins adipophilin (alias adipocyte differentiation-related protein) and butyrophilin were purified from bovine milk by reverse-phase chromatography. The nucleotide sequence of bovine adipophilin was obtained via peptide mapping and sequencing of a mammary gland cDNA clone, which comprises 1841 nucleotides and has an open reading frame of 450 amino acids. By peptide mapping, 19% of the amino acid sequence was confirmed. The obtained amino acid sequence has 87 and 80% identical residues with human and mouse adipophilin, respectively. Alignment with the proteins perilipin and TIP47 revealed two highly conserved segments, which may assemble into amphipathic alpha-helices.     

Long‐Range Domain Structure and Symmetry Engineering by Interfacial Oxygen Octahedral Coupling at Heterostructure Interface

In epitaxial thin film systems, the crystal structure and its symmetry deviate from the bulk counterpart due to various mechanisms such as epitaxial strain and interfacial structural coupling, which is accompanyed by a change in their properties. In perovskite materials, the crystal symmetry can be described by rotations of sixfold coordinated transition metal oxygen octahedra, which are found to be altered at interfaces. Here, it is unraveled how the local oxygen octahedral coupling at perovskite heterostructural interfaces strongly influences the domain structure and symmetry of the epitaxial films resulting in design rules to induce various structures in thin films using carefully selected combinations of substrate/buffer/film. Very interestingly it is discovered that these combinations lead to structure changes throughout the full thickness of the film. The results provide a deep insight into understanding the origin of induced structures in a perovskite heterostructure and an intelligent route to achieve unique functional properties.     

Electrical contact resistance between stainless steel bipolar plate and carbon felt in PEFC: A comprehensive study

Bipolar plate represents a key component of Proton Exchange Membrane Fuel Cell (PEFC) with several essential functions, among them the electric connection of elementary cells. Usually made of graphite, this component is studied worldwide in order to develop a commercially viable alternative: different ways have been being investigated, and to date, despite corrosion issues, stainless steel (SS) appears as a good candidate material, but its Electrical Contact Resistance (ECR) can reach unacceptable values when exposed to PEFC environment. This paper offers a comprehensive study of the parameters acting on ECR when using uncoated SS in PEFC: roughness, which influences the surface contact area with carbon baking, bulk composition of the alloy, which influences only partly the nature of passive films, and the composition and structure of passive films, strongly modified by surface treatments and ageing conditions.     

Expressing aspectual interactions in design: evaluating three AOM approaches in the slot machine domain

In the context of an industrial project, we evaluated the implementation of the software of a casino slot machine. This software has a significant amount of crosscutting concerns that depend on and interact with each other as well as with the modular concerns. We therefore wished to express our design using an appropriate aspect-oriented modeling approach. We therefore evaluated three candidate methodologies: Theme/UML, WEAVR, and RAM to establish their suitability. Remarkably, only the last of the three has shown to allow an adequate expression of the interactions, albeit not fully explicit. The first two fall short because half of the interaction types cannot be expressed at all while the other half need to be expressed using a work-around that hides the intention of the design. Neither does RAM allow a fully explicit expression of interactions, but it would be the most adequate approach for the slot machine case.     

Algorithm based decision support system for the concerted selection of equipment in machining/assembly cells

Equipment selection plays a major role in the performance of machining/assembly cells. Based on analytical algorithms, a decision support system (DSS) is developed to select machining centres and robots concurrently from the milieu available in the marketplace. The DSS evaluates the design and geometry of the mating parts that are to be processed and assembled by the cell. Accordingly, it recommends the machining centre and robot that maximize the cell's performance subject to various operational and budget constraints.     

A mesh adaptation framework for dealing with large deforming meshes

In this paper, we identify and propose solutions for several issues encountered when designing a mesh adaptation package, such as mesh‐to‐mesh projections and mesh database design, and we describe an algorithm to integrate a mesh adaptation procedure in a physics solver. The open‐source MAdLib package is presented as an example of such a mesh adaptation library. A new technique combining global node repositioning and mesh optimization in order to perform arbitrarily large deformations is also proposed. We then present several test cases to evaluate the performances of the proposed techniques and to show their applicability to fluid–structure interaction problems with arbitrarily large deformations. Copyright © 2009 John Wiley & Sons, Ltd.     

The flotation of magnetic and non-magnetic pyrrhotite from selected nickel ore deposits

The non-stoichiometric sulfide mineral pyrrhotite (Fe_(1?x)S), common to many nickel ore deposits, occurs in different crystallographic forms and compositions. A series of pyrrhotite samples derived from Canada, South Africa and Botswana whose mineralogy is well characterised, were selected here in order to develop the relationship between mineralogy and flotation performance. Using both oxygen uptake and microflotation tests, the behaviour of the different pyrrhotite types was compared in terms of the effect of pH and collector addition. Non-magnetic pyrrhotite was less reactive in terms of its oxygen uptake and showed the best collectorless flotation recovery. Magnetic pyrrhotite was more reactive and showed poor collectorless flotation performance that could be improved with the addition of xanthate collector, but only if it was not already passivated. These differences are interpreted to be a result of pyrrhotite mineralogy. This has implications that may aid the manipulation of pyrrhotite flotation performance in processing operations.     

Sintering of α-alumina for highly transparent ceramic applications

In this paper we present our results on the sintering of α alumina ceramics by hot isostatic pressing. It describes a simple method for obtaining precise relative density values on our almost 100% dense samples. Then, transparency results are discussed with respect to grain size and residual porosity measurements, comparing them to scattering calculations. Our results are not far from the best reported transmission values: almost 60% for a 1 mm thick sample. The other 40% diffuse light comes from the birefringence of alumina for the most part. However, they are transparent enough to see detailed structures at several kilometers through them.