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.     

A comparative study of many-objective evolutionary algorithms for the discovery of software architectures

During the design of complex systems, software architects have to deal with a tangle of abstract artefacts, measures and ideas to discover the most fitting underlying architecture. A common way to structure such complex systems is in terms of their interacting software components, whose composition and connections need to be properly adjusted. Along with the expected functionality, non-functional requirements are key at this stage to guide the many design alternatives to be evaluated by software architects. The appearance of Search Based Software Engineering (SBSE) brings an approach that supports the software engineer along the design process. Evolutionary algorithms can be applied to deal with the abstract and highly combinatorial optimisation problem of architecture discovery from a multiple objective perspective. The definition and resolution of many-objective optimisation problems is currently becoming an emerging challenge in SBSE, where the application of sophisticated techniques within the evolutionary computation field needs to be considered. In this paper, diverse non-functional requirements are selected to guide the evolutionary search, leading to the definition of several optimisation problems with up to 9 metrics concerning the architectural maintainability. An empirical study of the behaviour of 8 multi- and many-objective evolutionary algorithms is presented, where the quality and type of the returned solutions are analysed and discussed from the perspective of both the evolutionary performance and those aspects of interest to the expert. Results show how some many-objective evolutionary algorithms provide useful mechanisms to effectively explore design alternatives on highly dimensional objective spaces.     

A study of the suitability of the KENTORT II eastern shale oil for asphalt paving applications

The uncertain future of petroleum reserves has fuelled the search for alternative resources. A feasibility study was conducted to determine potential paving applications of the oil extracted from eastern shale by the KENTORT II process. The eastern shale oil (ESO) in this study was separated into two drastically different viscosity portions, designated as ‘hard’ and ‘soft’ ESO. It was hypothesized that the ‘hard’ portion might enhance the asphalt performance by increasing the stiffness. It was discovered that the ‘hard’ ESO modified asphalt properties deteriorate significantly with time. On the other hand, the ‘soft’ ESO was found to exhibit desirable properties in an asphalt recycling application. Further studies are recommended to fully characterize the binder and mixture properties of ESO modified/rejuvenated asphalts.     

Evaluation of Eulychnia acida and Echinopsis chiloensis (Cactaceae) extracts in inhibiting corrosion of carbon steel in HCl solution

In the present study, the activity of extracts obtained from the stems of two endemic species of the central–northern region of Chile (Eulychnia acida [Copao] and Echinopsis chiloensis [Quisco]), was evaluated as potential corrosion inhibitors for carbon steel in 0.1 M HCl. The total content of phenols and flavonoids in the extracts was determined, and the main components were identified by high-performance liquid chromatography–mass spectrometry, being similar in both species. The inhibition efficiency of extracts was evaluated by mass loss measures, Tafel polarization curves, and electrochemical impedance spectroscopy. The assay results showed similar values in inhibition percentages, around 88% at extract concentrations of 1,500 ppm. The adsorption on the steel surface followed the Langmuir model adsorption isotherm, whose thermodynamic parameters (ΔG°_ads for Copao and Quisco, −17.81 and −17.70 kJ/mol, respectively) suggest a physisorption mechanism. The scanning electron microscopy analyses showed that in the presence of the extracts, the surface of the steel is covered by a thin film that allows the sanding marks to be visualized; while without the extracts the surface is rough due to the HCl corrosion effect.     

Structure and physical properties of nickel manganite NiMn2O4 obtained from nickel permanganate precursor

In this paper we present the structural, magnetic and dielectric properties of ceramic nickel manganite NiMn₂O_4+δ produced by using nickel permanganate Ni(MnO₄)₂xH₂O as a precursor. We have characterized the NiMn₂O_4+δ stoichiometry using quantitative energy-dispersive analysis of X-rays and thermal gravimetry under reducing conditions. Increased oxygen and Mn⁴⁺ contents were detected. X-ray diffraction and Rietveld refinement of X-ray data were carried out. Temperature dependent magnetization measurements were performed and the ferri-magnetic transition was identified at ≈100 K. The ferri-magnetic moment was found to be ≈1μ_B and hysteretic magnetization vs applied field curves were obtained. Dielectric properties were measured using impedance spectroscopy. Two dielectric relaxation processes were detected, which were associated with grain boundary and bulk contributions. The Arrhenius plots of resistivity and the temperature dependent dielectric permittivity were obtained for the two relaxations by means of an equivalent circuit model based on a series of two parallel RC elements.     

Relationships of Gut Microbiota Composition,Short-Chain Fatty Acids and Polyamines with the Pathological Response to Neoadjuvant Radiochemotherapy in Colorectal Cancer Patients

Emerging evidence has suggested that dysbiosis of the gut microbiota may influence the drug efficacy of colorectal cancer (CRC) patients during cancer treatment by modulating drug metabolism and the host immune response. Moreover, gut microbiota can produce metabolites that may influence tumor proliferation and therapy responsiveness. In this study we have investigated the potential contribution of the gut microbiota and microbial-derived metabolites such as short chain fatty acids and polyamines to neoadjuvant radiochemotherapy (RCT) outcome in CRC patients. First, we established a profile for healthy gut microbiota by comparing the microbial diversity and composition between CRC patients and healthy controls. Second, our metagenomic analysis revealed that the gut microbiota composition of CRC patients was relatively stable over treatment time with neoadjuvant RCT. Nevertheless, treated patients who achieved clinical benefits from RTC (responders, R) had significantly higher microbial diversity and richness compared to non-responder patients (NR). Importantly, the fecal microbiota of the R was enriched in butyrate-producing bacteria and had significantly higher levels of acetic, butyric, isobutyric, and hexanoic acids than NR. In addition, NR patients exhibited higher serum levels of spermine and acetyl polyamines (oncometabolites related to CRC) as well as zonulin (gut permeability marker), and their gut microbiota was abundant in pro-inflammatory species. Finally, we identified a baseline consortium of five bacterial species that could potentially predict CRC treatment outcome. Overall, our results suggest that the gut microbiota may have an important role in the response to cancer therapies in CRC patients.     

Electro-oxidation kinetics of adsorbed CO on platinum electrocatalysts

We describe the voltammetric measurement of the full oxidation of adsorbed CO on unsupported platinum electrocatalysts, with concomitant cyclic voltammetry of the hydrogen adsorption and desorption. The hydrogen region of platinum is used to parse the platinum surface into sites associated with weakly bound (WB) hydrogen and strongly bound (SB) hydrogen. By monitoring changes in the hydrogen region while following the two observed CO oxidation peaks, we are able to identify the WB sites as being the most active sites for CO_ads electro-oxidation. The full oxidation peak is fitted to a model based on a modified Butler-Volmer equation that includes the two families of sites. Excellent agreement with experimental results is obtained, and the resulting fits yield the kinetic parameters for the two families of sites. When combined with coulometry, these kinetic analyses also show the importance of linear- and bridged-CO_ads species in the electro-oxidation process. Limitations of the model and the role of CO_ads dynamics amongst the various surface sites are discussed.