Mn‐peroxidase production by Panus tigrinus CBS 577.79: response surface optimisation and bioreactor comparison

This study reports the statistical optimisation through response surface methodology of the growth medium for Panus tigrinus manganese‐dependent peroxidase (MnP) production in shaken culture. Three crucial variables, including carbon source, malonic acid and Mn²⁺, were optimised in a nitrogen‐limited medium. Sucrose was the best carbon source for MnP production. Mn²⁺ ions and malonic acid significantly stimulated MnP production at an optimal concentration of 53 mg dm^?3 and 8.2 mmol dm^?3, respectively, resulting in 0.83 U cm^?3. Further experiments were performed in lab‐scale stirred tank (STR) and bubble‐column (BCR) reactors using the previously optimised liquid medium. BCR proved to be more adequate than STR in supporting MnP production, leading to 3700 U dm^?3 after 144 h with a productivity of 25.7 U dm^?3 h^?1. On a comparative basis with other production data in lab‐scale reactors, these results appear to be compatible with scale transfer. Copyright © 2006 Society of Chemical Industry     

The influence of dietary lipid source on quality characteristics of raw and processed chicken meat

The influence of dietary lipid source [animal fats (AF) and vegetable oils (VO)] on quality characteristics of raw chicken meat (breast, thigh and meat batter) and cooked breaded patties prepared using a conventional technology (CT; forming, battering, breading, frying and convection cooking) or innovative technology (IT; forming, pre-dusting, steam cooking, battering and frying) was evaluated. Overall, dietary lipid source did not influence the chemical composition of raw meat while it modified its colour (L*, a*, b*). With respect to AF, VO produced higher breast and thigh meat cooking losses as well as a lower moisture and higher protein content of cooked breaded patties. VO also determined an increase of polyunsaturated-to-saturated fatty acid ratio of both raw and processed meat. Despite the different fatty acid profiles, the oxidative status of lipids was not affected by dietary lipid source and was acceptable in both raw meat and cooked patties as indicated by peroxide and thiobarbituric acid reactive substance values. As for the processing technology, IT determined a higher moisture and lower lipid content of the cooked breaded patties. Moreover, lipolysis degree was slightly higher in the products coming from IT. Finally, patties from AF group were lighter and more yellow than products belonging to VO group whereas IT led to lighter, less red and more yellow patties in comparison to CT.     

The LAI test in specific immune-reactivity studies of fibrocytic breast disease

Sixteen cases of fibrocystic breast disease at different histopathologic stages were examined with the leukocyte adherence inhibition assay. Skeletal muscle and gastric carcinoma extracts were used as controls. The glass adherence of leukocytes from patients affected by fibrocystic breast disease was more inhibited when extracts from breasts with fibrocystic disease were used rather than control extracts. Nonadherence indexes (NAIs) were high in 8 cases, around 20 in 4 cases, a little above zero in 2 cases and below zero in 2 cases. NAIs were related to the histopathologic stage: the highest NAIs were found in 8 cases of classic fibrocystic disease, the lowest in 1 case of simple breast fibrosis.     

New photoactive oligo- and poly-alkylthiophenes

A new type of ω-methoxy-functionalized oligo-(OCT) and poly-(PQ) hexylthiophene characterized by a tetrameric repeating unit was synthesized and characterized. The configurational regularity and the mean degree of functionalization per thiophenic ring, lower than in commonly synthesized PATs, permitted the obtainment of more ordered chain conformations especially in the solid (film) state. Solar cells based on OCT and PQ films (as p-donor polymeric layer) mixed with Single-walled Carbon Nanotubes (SWCNTs, used as electron-acceptor system) were prepared and investigated. A power conversion efficiency of 0.52% with a fill factor of 0.42, an open-circuit voltage of 0.48 V and a short-circuit current of 1.93 mA/cm² under 70 mW/cm² white light illumination is reported for the polymeric sample. The obtained performance is comparable with that of devices made with regioregular P3HT but the easiness of the monomer synthesis and polymer preparation, giving OCT and PQ with good yields, as well as the enhanced workability and filmability of the latters from diluted solutions of common organic solvents together with their low sensitivity to the environmental conditions (air oxygen, moisture, temperature) makes the synthesized materials very promising for the set-up of polymer photovoltaic cells.     

Results of acoustic and temperature noise measurements on sodium cooled electrically heated 7 rod bundle

Assembly cooling deficiency in a LMFBR is one of the most important safety problems for reactor design and operation.

Studies on early detection and diagnosis of local accident by means of noise analysis techniques have been initiated at CNEN. Acoustic and temperature noise measurements have been carried out on a 7 rod bundle during slow power transients up to boiling conditions. The test section, simulating the italian PEC reactor fuel element, was mounted on ENA-2 sodium loop located at the CSN Casaccia.

Acoustic noise spectral analysis up to 32 kHz shows the appearance, in presence of boiling, of power increase at certain frequencies. Power spectra and rms values are updated and recorded every 0.3 sec and show large variations going from single phase to boiling.

Temperature noise spectral analysis shows that the power, between 1 and 50 Hz, increases, in presence of boiling, by a factor bigger than 30. It has been tested the sensitivity of other indicators of the temperature fluctuations, like skewness and flatness, to reveal boiling.     

Advances in Lee–Schetzen Method for Volterra Filter Identification

This paper concerns the identification of nonlinear discrete causal systems that can be approximated with the Wiener–Volterra series. Some advances in the efficient use of Lee–Schetzen (L–S) method are presented, which make practical the estimate of long memory and high order models. Major problems in L–S method occur in the identification of diagonal kernel elements. Two approaches have been considered: approximation of gridded data, with interpolation or smoothing, and improved techniques for diagonal elements estimation. A comparison of diagonal elements estimated, with different methods has been shown with extended tests on fifth order Volterra systems.First Online Version Published in July, 2005     

On learning vector-valued functions

In this letter, we provide a study of learning in a Hilbert space of vectorvalued functions. We motivate the need for extending learning theory of scalar-valued functions by practical considerations and establish some basic results for learning vector-valued functions that should prove useful in applications. Specifically, we allow an output space Y to be a Hilbert space, and we consider a reproducing kernel Hilbert space of functions whose values lie in Y. In this setting, we derive the form of the minimal norm interpolant to a finite set of data and apply it to study some regularization functionals that are important in learning theory. We consider specific examples of such functionals corresponding to multiple-output regularization networks and support vector machines, for both regression and classification. Finally, we provide classes of operator-valued kernels of the dot product and translation-invariant type.     

Robots in a domestic setting: a psychological approach

The study presented in this paper aims at improving the current understanding of human-robot interaction by adopting a psychological approach. The acceptability of robotic devices in home settings, especially by elderly people, does not depend only on the practical benefits they can provide, but on complex relationships between the cognitive, affective and emotional components of peoples images of robots. This study has investigated the main dimensions of these representations, by comparing the attitudes towards technology in general, and domestic robots in particular, held by people at different stages of the lifespan. The results confirm that age is a critical variable.     

Seasonal chemical–physical changes of PGI Pachino cherry tomatoes detected by magnetic resonance imaging (MRI)

Magnetic resonance imaging (MRI) has been used to study the variations of internal structure and chemical–physical characteristics of cherry tomatoes (Lycopersicon esculentum cv. Shiren), one the most economically valuable horticultural crops, in different harvesting seasons. In particular, the study focused on PGI (Protected Geographical Indication) Pachino cherry tomatoes, characterised by taste and nutritional value, notably in the winter production, amounting about 500 ton/year.