Hydrotreating data interpretation by chemometrics

Hydrotreating in the presence of dispersed catalysts has been considered a promising route to obtain valuable fuels from heavy hydrocarbon cuts. A laboratory-scale study on the effect of operating conditions on heavy feedstock hydrotreating performances is reported. In order to maximise the effectiveness of the research activity, chemometrics was exploited both for experimental design and data interpretation.     

A Bifunctional Copper Catalyst for the One Pot-One Step Esterification?+?Hydrogenation of Tall Oil Fatty Acids

An efficient copper catalyst for the one-pot one-step hydrogenation?+?esterification of unsaturated free fatty acids is described. The high selectivity in hydrogenation promoted by copper, combined with the high activity in esterification observed with solid mixed oxides allows one to directly obtain stabilized methyl esters.     

Evaluation of antioxidant capacity of some fruit and vegetable foods: efficiency of extraction of a sequence of solvents

All methods for assessing the total antioxidant capacity (TAC) of food samples are strongly affected by the solvents used during extraction. In recent years a sequential solvent extraction procedure utilising water and acetone has been widely used for TAC measurements of foods. To better understand the efficiency of this procedure in terms of the amount of extracted antioxidants and the subsequent measurement of TAC, two vegetables (onion and spinach) and two fruits (orange and tomato) were sequentially extracted with water, acetone and chloroform. Each extract fraction was analysed separately for its content of known antioxidant compounds by specific procedures and for its TAC by the Trolox equivalent antioxidant capacity assay. The results showed that the compounds in the water and acetone extracts were the main contributors to TAC. The chloroform extracts did not contribute to TAC, with the exception of the spinach extract, owing to the presence of low levels of carotenoids. In conclusion, the analysed extraction procedure was more effective for foods rich in water‐soluble antioxidants than for those rich in lipid‐soluble antioxidants. Copyright © 2006 Society of Chemical Industry     

A tool supporting efficient model checking of concurrent specifications

We show a tool supporting efficient model checking of LOTOS programs. LOTOS is a well-known specification language for concurrent and distributed systems. The main functionality of the tool is the syntactic reduction of a program with respect to a logic formula expressing a property to be checked. The method is useful to reduce the state-explosion problem in model checking. The tool is integrated with the Concurrency Workbench of North Carolina. The tool also supports a windows user interface.     

Suitability of selected autochthonous lactic acid bacteria cultures for Pecorino Sardo Dolce cheese manufacturing: influence on microbial composition,nutritional value and sensory attributes

The use of an autochthonous starter culture made up by Streptococcus thermophilus, Lactococcus lactis subsp. lactis, Lactobacillus plantarum and Lactobacillus casei in the production of experimental Pecorino Sardo Dolce PDO resulted in a high presence of presumptive mesophilic lactococci and lactobacilli, ~10 log colony‐forming units (cfu), and in significantly higher amount of total free amino acids and free fatty acids, 195.1 vs 178.9 and 328.6 vs 191.8 mg/100 g of experimental vs control cheese (made using a commercial starter) respectively. The experimental cheese also displayed better sensory properties such as taste and aftertaste.     

Internal quality and antioxidants content of cold-stored red sweet peppers as affected by polyethylene bag packaging and hot water treatment

Physical (weight, firmness) and compositional (sugars, organic acids, ascorbic acid, phenolic compounds and carotenoids) changes of red sweet peppers (Capsicum annuum L.) were monitored during 21 days of cold storage (at 7.5 °C); fruits were stored without packaging, packaged in low density polyethylene bags, or after hot water dipping (53 °C for 4 min) and packaging. Packaging prevented water loss, and preserved the firmness of the fresh product. Sugars (fructose and glucose) content was practically constant throughout the whole storage time, for all treatments. A moderate accumulation of citric acid was observed during storage, but no marked effects of packaging and hot water dipping on citric and malic acid content. Ascorbic acid content slightly increased in unpackaged and packaged fruits, but not in treated+packaged peppers. Hydroxycinnamics total content seemed not to be affected by cold storage, packaging or hot water treatment, whereas glycosylated flavonoids showed somewhat lowered levels during storage, particularly in the case of unpackaged and packaged+treated fruits. Regarding carotenoids content, the effect of the considered storage conditions seemed to be much smaller than that due to ripening stage. Provitamin A content showed an increasing trend in unpackaged and packaged fruits; packaged+treated peppers were characterised by a lower retention of provitamin A and a higher level of capsanthin and cucurbitaxanthin A with respect to not treated fruits. On the whole, packaging and hot water treatment did not produce noticeable adverse effects on the majority of the examined compositional quality parameters.     

PCSK9 Affects Astrocyte Cholesterol Metabolism and Reduces Neuron Cholesterol Supplying In Vitro: Potential Implications in Alzheimer’s Disease

The Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) involvement in Alzheimer’s disease (AD) is poorly investigated. We evaluated the in vitro PCSK9 modulation of astrocyte cholesterol metabolism and neuronal cholesterol supplying, which is fundamental for neuronal functions. Moreover, we investigated PCSK9 neurotoxic effects. In human astrocytoma cells, PCSK9 reduced cholesterol content (−20%; p < 0.05), with a greater effect in presence of beta amyloid peptide (Aβ) (−37%; p < 0.01). PCSK9 increased cholesterol synthesis and reduced the uptake of apoE-HDL-derived cholesterol (−36%; p < 0.0001), as well as the LDL receptor (LDLR) and the apoE receptor 2 (ApoER2) expression (−66% and −31%, respectively; p < 0.01). PCSK9 did not modulate ABCA1- and ABCG1-cholesterol efflux, ABCA1 levels, or membrane cholesterol. Conversely, ABCA1 expression and activity, as well as membrane cholesterol, were reduced by Aβ (p < 0.05). In human neuronal cells, PCSK9 reduced apoE-HDL-derived cholesterol uptake (−41%; p < 0.001) and LDLR/apoER2 expression (p < 0.05). Reduced cholesterol internalization occurred also in PCSK9-overexpressing neurons exposed to an astrocyte-conditioned medium (−39%; p < 0.001). PCSK9 reduced neuronal cholesterol content overall (−29%; p < 0.05) and increased the Aβ-induced neurotoxicity (p < 0.0001). Our data revealed an interfering effect of PCSK9, in cooperation with Aβ, on brain cholesterol metabolism leading to neuronal cholesterol reduction, a potentially deleterious effect. PCSK9 also exerted a neurotoxic effect, and thus represents a potential pharmacological target in AD.