Bacteriocinogenic activity from starter cultures used in Spanish meat industry

Thirty-nine bacterial strains, obtained from commercial starter cultures and commonly used by the meat industry in Spain, have been examined for their ability to produce bacteriocins. Fourteen (35%) of them showed antagonism against at least one of the indicator strains, by the agar spot test. The strains showing an inhibitory action against pathogenic indicator strains were identified as Pediococcus acidilactici, Lactobacillus curvatus, Lactobacillus pentosus and Lactobacillus plantarum, which showed an inhibitory action against a wide range of Gram-positive bacteria. The only strain which showed reliable inhibitory activity against pathogenic indicator strains, by the well diffusion assay, was P. acidilactici. This strain produces an inhibitory compound, which reaches its maximum activity at the beginning of the stationary phase of growth. This antimicrobial substance (bacteriocin) has a proteinaceous nature, is stable over a broad range of pH, resistant to heat and shows a bactericidal action.     

Physicochemical, microbiological and sensory profiles of fermented milk containing probiotic strains isolated from kefir

A two-strain starter culture containing Lactobacillus plantarum CIDCA 83114, a potential probiotic strain isolated from kefir grains, and Streptococcus thermophilus CIDCA 321 was tested for the preparation of a fermented milk product. Kluyveromyces marxianus CIDCA 8154, a yeast with immunomodulatory properties was included to formulate a three-strain starter culture. Supernatants of enterohaemorragic Escherichia coli, shiga-toxin-producing strain, along with a two-strain or a three-strain starter culture were included in the medium of Vero-cell surface cultures. The results demonstrated that these combinations of microorganisms antagonize the cytopathic action of shiga toxins. The cell concentration of Lb. plantarum did not decrease during fermentation, indicating that the viability of this strain was not affected by low pH, nor did the number of viable bacteria change during 21 days of storage in either fermented products. The number of viable yeasts increases during fermentation and storage. Trained assessors analyzed the general acceptability of fresh fermented milks and considered both acceptable. The milk fermented with the two-strain starter culture was considered acceptable after two week of storage, while the product fermented with the three-strain starter culture remained acceptable for less than one week. The main changes in sensory attributes detected by the trained panel were in sour taste, milky taste and also in fermented attributes. The correlation between different sensory attributes and acceptability indicated that the panel was positively influenced by milky attributes (taste, odour, and flavour) as well as the intensity of flavour. In conclusion, the two-strain starter culture would be the more promising alternative for inclusion of that potential probiotic lactobacillus in a fermented milk product.     

Relation between the cavity detuning and the output opticalintensity in free-electron lasers

The authors use a simple model of saturation in free-electron lasers operating with pulsed beams to study the intensity growth as a function of the cavity mismatch and of the coupling parameter. In spite of the simplicity of the model, the dependence of the intracavity power, as a function of the cavity detuning, is reproduced remarkably well. It is also pointed out that an enhancement of the optical power is obtained by adjusting the cavity length while the optical signal grows. The problem is analyzed qualitatively and realization schemes are proposed     

The identification of the switching field distribution components

A direct method for measuring the ratio of the interaction field distribution and the critical field distribution in a wide variety of longitudinal recording media is presented. The method requires only the measurement of m_p, the normalized remanence of the sample at the conclusion of the magnetizing process H_sal, -h_ci , +h_ci, where H_sat is a field large enough to saturate it and h_ci is the operative remanence coercivity. In conjunction with major loop measurements, the method obtains both the standard deviation in the interaction field distribution and the standard deviation in the critical field distribution. Experimental verification of the proposed technique is presented     

Spice use in food: Properties and benefits

Spices are parts of plants that due to their properties are used as colorants, preservatives, or medicine. The uses of spices have been known since long time, and the interest in the potential of spices is remarkable due to the chemical compounds contained in spices, such as phenylpropanoids, terpenes, flavonoids, and anthocyanins. Spices, such as cumin (cuminaldehyde), clove (eugenol), and cinnamon (cinnamaldehyde) among others, are known and studied for their antimicrobial and antioxidant properties due to their main chemical compounds. These spices have the potential to be used as preservatives in many foods namely in processed meat to replace chemical preservatives. Main chemical compounds in spices also confer other properties providing a variety of applications to spices, such as insecticidal, medicines, colorants, and natural flavoring. Spices provide beneficial effects, such as antioxidant activity levels that are comparable to regular chemical antioxidants used so they can be used as a natural alternative to synthetic preservatives. In this review, the main characteristics of spices will be described as well as their chemical properties, different applications of these spices, and the advantages and disadvantages of their use.     

Regional science: economy and geography in France and French-speaking countries

The objective of this paper is to assess the French-speaking countries contributions to regional science since its creation in the 1950s. France, and other French-speaking countries, very quickly adhered to the approach of the founding fathers of regional science. French-language research developed for several years without maintaining major relations with the main streams that flow through regional science. However, the years 2000 and 2010 saw the emergence of streams of thought that strongly irrigate at the international level. The authors of this paper are part of this movement. Here we trace the origins and development of the French-speaking contribution to regional sciences, while highlighting the originality of the French-language approach. First, the question of academic and institutional contexts is discussed, with the role of the founders and the peculiar place of Journals and public institutions. Further sections analyse the main contributions coming from economics (local systems of production and innovation, innovative milieus and proximity analysis) and geography (regional development at a global scale, and urban systems and complexity). We conclude with cross-disciplinary contributions including intra-urban organization and mobility, territorial governance and territorial development, as well as other approaches to the social sciences, in the contemporary issues of city and territorial governance.     

A Statistical Determination of the Transit Speed of Pollutants in a Water Reservoir Affected by Acid Mine Drainage from the Iberian Pyrite Belt

The El Sancho reservoir is located in the Odiel River basin, which crosses the Iberian Pyrite Belt. The reservoir receives acid mine drainage (AMD) from the Meca River, a tributary of the Odiel River. Two multi-parameter probes, one placed at the tail (up-gradient) end of the reservoir, where the contaminants enter, and another close to the reservoir dam were used to characterize acidity migration through the Sancho reservoir. The probes both measured pH and conductivity every 30 min. Two different levels of contamination were found, due to dilution that takes place within the reservoir and changes in the AMD composition. The cross-correlation function allowed quantification of the migration process from tail to dam. For both pH and conductivity, the maximum correlation occurred 17 days after sampling, indicating a mean transit time of 17 days. Since the distance between the two sampling points was 14,500 m, the contaminant transit speed was 0.0098 m/s.     

Optimization methods in inverse problems and applications to science and engineering

Optimization and Engineering -     

CLASSIFICATION OF MULTI-LOOK POLARIMETRIC SAR IMAGERY AND POLARIZATION CHANNEL OPTIMIZATION

In this paper, a new maximum likelihood (ML) classification algorithm is proposed to classify the multi-look polarimetric synthetic aperture radar (SAR) imagery. Experimental results with the NASA/JPL airborne L-band polarimetric SAR data demonstrate the effectiveness of the new algorithm. Furthermore, when using the algorithm in the classifications with subsets of the multi-look polarimetric SAR data, the polarization-channel optimization for the terrain type classification is implemented.     

Search for Related Substances in Market Products Containing Enalapril Maleate as the Active Principle

This study's main object was the determination of substances, by means of high-performance liquid chromatography (HPLC), that are related to enalapril maleate in medicinal tablets. The research was on products containing a 20 mg active principle with a 12-month Δt and on those batches near their expiration date with an enalapril maleate concentration of 10, 5, and 2.5 mg.