Assuring property conformance of code generators via model checking

Automatic code generation is an essential cornerstone of today’s model-driven approaches to software engineering. Thus a key requirement for the success of this technique is the reliability and correctness of code generators. This article describes how we employ standard model checking-based verification to check that code generator models developed within our code generation framework Genesys conform to (temporal) properties. Genesys is a graphical framework for the high-level construction of code generators on the basis of an extensible library of well-defined building blocks along the lines of the Extreme Model-Driven Development paradigm. We will illustrate our verification approach by examining complex constraints for code generators, which even span entire model hierarchies. We also show how this leads to a knowledge base of rules for code generators, which we constantly extend by e.g. combining constraints to bigger constraints, or by deriving common patterns from structurally similar constraints. In our experience, the development of code generators with Genesys boils down to re-instantiating patterns or slightly modifying the graphical process model, activities which are strongly supported by verification facilities presented in this article.     

Oxidative stabilization of ultra-high omega-3 concentrates as ethyl esters or triacylglycerols

A comparative study of the oxidative stability of “ultra-high” ω3 concentrates (80%) from fish oils as triacylglycerols (TAG) or ethyl esters (EE), as well as their stabilization by supercritical extracts of rosemary (SER), α-tocopherol or their mixture, by Rancimat method and throughout storage time, was carried out. No significant differences were found between EE and TAG on oxidative stability when measured by Rancimat conditions in the range of 50?90 °C. However, storage experiments revealed a poor stability of the EE concentrate form, measured by the monitorization of peroxide and p-anisidine values. Concerning the stabilization by antioxidants, there was a lack of antioxidant effect of evaluated compounds when Rancimat assays were performed at 70 °C, whereas an antioxidant effect began to evidence at 60 °C, and a clearest antioxidant protection was measured at 50 °C for the mixture of the SER plus α-tocopherol in both EE and TAG forms. This selected binary mixture efficiently stabilized the ω3-TAG concentrate throughout 50 days of storage conditions, whereas the stabilization of ω3-EE concentrate was worse. Therefore, the combination of SER and α-tocopherol seemed to be a good antioxidant mixture for the efficient stabilization of extremely labile ultra-high ω3 concentrates, especially in the form of ω3 TAG oils.     

PGC-1s in the Spotlight with Parkinson’s Disease

Parkinson’s disease is one of the most common neurodegenerative disorders worldwide, characterized by a progressive loss of dopaminergic neurons mainly localized in the substantia nigra pars compacta. In recent years, the detailed analyses of both genetic and idiopathic forms of the disease have led to a better understanding of the molecular and cellular pathways involved in PD, pointing to the centrality of mitochondrial dysfunctions in the pathogenic process. Failure of mitochondrial quality control is now considered a hallmark of the disease. The peroxisome proliferator-activated receptor gamma coactivator 1 (PGC-1) family acts as a master regulator of mitochondrial biogenesis. Therefore, keeping PGC-1 level in a proper range is fundamental to guarantee functional neurons. Here we review the major findings that tightly bond PD and PGC-1s, raising important points that might lead to future investigations.     

Simulation and optimization of supercritical fluid purification of phytosterol esters

Supercritical carbon dioxide extraction to separate phytosterol esters from fatty acid esters and tocopherols was simulated and optimized using the group contribution equation of state. Experimental extraction data at 328 K, pressures ranging from 200 to 280 bar and solvent‐to‐feed ratio around 25, was employed to verify the performance of the thermodynamic model. The raw material is the product obtained after a two‐step enzymatic reaction carried out on soybean oil deodorizer distillates, and contains mainly fatty‐acid ethyl esters, tocopherols and phytosterol esters. The extraction process was simulated using model substances to represent the complex multicomponent feed material. Nonlinear programming techniques were applied to find out optimal process conditions for a steady‐state countercurrent process with partial reflux of the extract. The process optimization procedure predicts that a product with 94.2 wt % of phytosterol ester purity and 80% yield could be achieved. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Isolation and Characterization of Squamous Cell Carcinoma-Derived Stem-like Cells: Role in Tumor Formation

In human epidermis, keratinocyte stem cells (KSC) are characterized by high levels of β₁-integrin, resulting in the rapid adhesion to type IV collagen. Since epithelial tumors originate from KSC, we evaluated the features of rapidly adhering (RAD) keratinocytes derived from primary human squamous cell carcinoma of the skin (cSCC). RAD cells expressed higher levels of survivin, a KSC marker, as compared to non-rapidly adhering (NRAD) cells. Moreover, RAD cells proliferated to a greater extent and were more efficient in forming colonies than NRAD cells. RAD cells also migrated significantly better than NRAD cells. When seeded in a silicone chamber and grafted onto the back skin of NOD SCID mice, RAD cells formed tumors 2–4 fold bigger than those derived from NRAD cells. In tumors derived from RAD cells, the mitotic index was significantly higher than in those derived from NRAD cells, while Ki-67 and survivin expression were more pronounced in RAD tumors. This study suggests that SCC RAD stem cells play a critical role in the formation and development of epithelial tumors.     

Deacidification of olive oil by countercurrent supercritical carbon dioxide extraction: Experimental and thermodynamic modeling

Supercritical carbon dioxide was used as an extractive solvent to remove free fatty acids from cold-pressed olive oil. Crude oil of different acidity content (from 0.5 to 4.0 wt%) was extracted in a packed column at 313 K and pressures of 180, 234 and 250 bar. The group contribution equation of state was employed to simulate the separation process, representing the oil as a simple pseudo-binary oleic acid + triolein mixture. Despite the simple representation of oil composition to simulate the deacidification process, a satisfactory agreement between the experimental and calculated yields and acidity of raffinates was obtained. The thermodynamic model was employed to study a continuous countercurrent multistage extraction process which yielded a raffinate having acidity lower than 0.7 wt%, when crude olive oil with different FFA content was processed.     

Chemo‐ and Stereodivergent Preparation of Terminal Epoxides and Bromohydrins through One‐Pot Biocatalysed Reactions: Access to Enantiopure Five‐ and Six‐Membered N‐Heterocycles

Different enantiopure terminal epoxides or bromohydrins have chemoselectively been synthesised in one‐pot starting from the corresponding α‐bromo ketones through alcohol dehydrogenase (ADH)‐catalysed processes adding an organic co‐solvent and tuning appropriately the medium pH and the temperature. Thus, at neutral pH enantiopure bromohydrins were obtained while using basic conditions (pH 9.5–10) epoxides were isolated as the main product. Furthermore, by simple selection of the biocatalyst, chemo‐ and stereodivergent transformations were achieved to obtain, e.g., enantiopure prolinol or piperidin‐3‐ol.     

Effect of aging in new oak, one-year-used oak, chestnut barrels and bottle on color, phenolics and gustative profile of three monovarietal red wines

This study provides specific information about the influence of storage in bottle and in 225-L barrels made from oak (new and used for 1 year) and chestnut wood on color indexes, spectrophotometric evaluable polyphenols, anthocyanins, phenolic acids and gustative attributes of three monovarietal red wines (Piedirosso, Cabernet Sauvignon and Merlot). The results of the analysis of variance show that wood type has a significant influence on chromatic characteristics, on vanilline reactive flavans, on low molecular weight phenolics and on astringency of wines. The effect depends on the type of wine. Therefore, both traditional and alternative wood containers could be used as an instrument to regulate the polymerization, oxidation and copigmentation reaction of wine phenolics and the sensory properties of red wine. The maturation in chestnut wood could be an interesting challenge to widen the supply of red wines maturated in wood, but its use needs more care than oak.