Isolation and sequence of the MIG1 homologue from the yeast Candida utilis

The Mig1p repressor from the food yeast Candida utilis has been isolated using a homologous PCR hybridization probe. This probe was amplified with two sets of degenerate primers designed on the basis of highly conserved motifs in the DNA-binding region (zinc-finger domain) from yeast Mig1p and fungi CreA repressors. The cloned gene was sequenced and found to encode a polypeptide of 345 amino acids which shows significant identity with other yeast and fungus repressors in the DNA-binding domain and also with the yeast Mig1 proteins in the C-terminal region (effector domain). The MIG1 repressor gene from C. utilis was able to complement functionally the mig1 mutation of S. cerevisiae. The sequence presented here has been deposited in the EMBL data library under Accession No. AJ277830.     

Distribution of bovine milk sialoglycoconjugates during lactation

The sialoglycoconjugate content of human milk has been extensively studied. However, little attention has been paid to the changes occurring in these compounds in bovine milk during lactation. Since sialoglycoconjugates are very abundant in milk from the early stages of lactation, they have been suggested to be important for the nutrition of the newborn during the first months of life. The distribution of sialoglycoconjugates (expressed as glycoconjugate-bound sialic acid) from four different stages of lactation (colostrum, transitional, mature, and late-lactation milks) was investigated in four Spanish-Brown cows. All the fractions studied (total sialic acids, glycoproteins, oligosaccharides, casein, and gangliosides) showed a similar trend. We found the highest values in the colostrum, these decreasing in transitional and mature milks and increasing again in late-lactation milk. We also found a selective change in the relative contents of glycoprotein- and oligosaccharide-bound sialic acids. In mature milk, the latter increased up to 80% (59% in colostrum) and the former decreased to 3.9% (35.3% in colostrum). It would appear that the decrease in oligosaccharide-bound sialic acid is compensated by the increase in glycoprotein-bound sialic acid. From these results, it is deduced that newborn infants or calves fed with infant formulas or milk replacers, respectively, should be supplemented with sialoglycoconjugates to approximate the composition of human and cow milk as far as is practicable.     

Methodology for Predicting the Phase Envelope of a Heavy Crude Oil and Its Asphaltene Deposition Onset

Abstract

We have presented general ideas to develop a new theoretical methodology, based on molecular simulation and equations of state, for obtaining the phase envelope and to predict pressure, volume, temperature (PVT) conditions of asphaltene precipitation by only taking into account the composition of the heavy crude oil and an asphaltene average molecular structure. Those results show that asphaltene precipitation is a reversible thermodynamic process. The precipitated phase is a liquid phase which consists of mainly asphaltene and some heavy fractions from the crude. This methodology can be applied to find complete phase diagrams of different crude oils based on an asphaltene average molecular structure and the composition of crude oil.     

Nonlinear thermal analysis of multi-holed lightweight concrete blocks used in external and non-habitable floors by FEM

The aim of this current and innovative work is the numerical thermal analysis of multi-holed lightweight concrete blocks for external and non-habitable floors by the finite element method (FEM). Twelve different block designs with the same external dimensions 0.57 × 0.45 × 0.20 m were built varying the number of the horizontal intermediate bulkheads, from 3 to 12. Besides, five different compositions of the lightweight aggregate concrete (LWAC) and five different bulk temperatures have been taken into account, giving place to a total of 600 different floor configurations, 300 cases per each heat flow direction: upward and downward heat flows. A nonlinear thermal problem is solved for all cases analysed and then, it is possible to choose the best candidate block from the standard rule requirements. Mathematically, the nonlinearity due to the radiation boundary condition inside the inner recesses of the blocks is tackled by the matrix radiation method. Once the nonlinear thermal problem is solved, the temperature distribution is obtained and the thermal characteristic values of the floors, both for downward and upward heat flows, are calculated. From the numerical results, we can conclude that the main variables in the thermal performance are the total number of recesses and the material conductivities. Therefore, increasing the number of horizontal intermediate bulkheads and decreasing the material conductivities, the best thermal efficiency is obtained. The selection of the best candidate block of external floors and floors in contact with non-habitable spaces is carried out through the following parameters: the average mass overall thermal efficiency and the equivalent thermal conductivity. Finally, detailed instructions are provided in order to select the appropriate floor satisfying the standard rule requirements and conclusions of this work are exposed.     

Developing and applying a GIS-assisted approach to evaluate visual impact in wind farms

Wind energy represents one of the most important renewable resources. Wind energy is a clean, renewable and its benefits are considered greater than the disadvantages. However, even though wind farms represent environmentally friendly projects, they frequently generate public resistance.One of the main disadvantages of wind farm construction projects is their poor aesthetic integration into the landscape. On the other hand, landscape impact of wind farms could be minimised if the visual impact is previously evaluated.As regards with the European legislation, the procedure of environmental impact assessment study is necessary before a wind farm project could be established. In contrast, there is not an objective methodology to assess the visual impact of wind farms.The aim of this work was to develop a methodology to predict and evaluate, before its construction, the visual impact of wind farms, taking into account the visualscape from different observation points.Proposed methodology could help to determine and evaluate the best location for new wind farm projects. Moreover, this method could be used as a consulting tool for public organization and private institutions, being quick, concise and clear.     

Lipid stability in powdered infant formula stored at ambient temperatures

Lipid stability of standard infant formula was evaluated at ambient temperatures, namely 25, 30 and 37 °C, during 3 months. Lipids were thoroughly analysed to evaluate changes in fatty acid composition and trans fatty acid isomers, non‐volatile oxidation compounds including oxidised, dimeric and polymeric triacylglycerols, and tocopherol. No significant changes in either of the parameters examined were found in total lipids extracted from infant formula along the storage period. However, the minor free oil fractions (about 7.5% of total lipids) showed a significant increase in oxidation compounds and marked decrease in tocopherol levels during storage at all temperatures. Samples stored at 37 °C for 3 months were rancid and, accordingly, contained the highest oxidation level in the free oil fraction, whereas total lipids extracted were apparently not oxidised. Results showed the necessity of analysing separately the free oil fraction in infant formulae to obtain a clear picture of the oxidation status.     

Development of a polymerase chain reaction assay for species identification of goose and mule duck in foie gras products

Polymerase chain reaction amplification of a conserved region of the -actin gene has been used for the specific identification of goose (Anser anser) and mule duck (Anas platyrhynchos×Cairina moschata) foie gras. Universal primers were used for the amplification of a DNA fragment containing three introns and four exons of the -actin gene in goose and mule duck. Sequence analysis of the amplified fragments was necessary for the design of forward species-specific primers in the goose and mule duck -actin genes. The use of species-specific forward primers, together with a reverse universal primer, produced amplicons of different length, allowing clear identification of goose and mule duck foie gras samples. Analysis of experimental mixtures demonstrated that 1% of duck can be easily detected in goose foie gras using the PCR method developed here. This genetic marker can be very useful for the accurate identification of these two species in foie gras products.     

Effect of selected yeast strains on the sensory properties of dry fermented sausages

This study examines the role of yeasts in the sensorial characteristics of dry fermented sausages. A total of 172 yeast strains were isolated from commercially obtained dry fermented sausages and their enzymatic activities studied. Those most active against meat proteins and pork fat were selected. Experimental sausages were manufactured and the yeasts inoculated onto the surface or into the mince. Control batches were manufactured similarly, but without inoculation. After ripening, the composition of the protein and lipid fractions were studied. The sensory properties of the products were evaluated by trained judges. Despite the enzymatic activity of the yeasts, the organoleptic characteristics of the sausages—irrespective of inoculation site—did not differ significantly from those of the controls. The influence of yeasts on the ripening of dry fermented sausages is, therefore, doubtful.     

Occurrence of salmonellae in retail chicken carcasses and their products in Spain

This study examined the incidence of Salmonella in Spanish poultry products. Samples included chicken carcasses, chicken parts (wings, legs and giblets-livers and hearts) and processed chicken products (red sausages, white sausages and hamburgers). The average detection rate was 49%, with the highest (55%) in chicken carcasses (skin) and the lowest (20%) in hamburgers. The chicken carcasses purchased in supermarkets were more contaminated (75%) than those from poulterers shops (25%). Salmonella Enteritidis, S. Poona, S. Paratyphi B and S. Worthington were isolated in 34.3%, 11.4%, 2.8% and 1.4% of the samples, respectively. One (1.4%) red sausage sample harboured two serotypes (S. Enteritidis and S. Worthington). This fact emphasizes the usefulness of subtyping several Salmonella isolates from the same sample in epidemiological studies.