Effects of different culture conditions on biological potential and metabolites production in three Penicillium isolates

The genus Penicillium is well known for its importance in drug and food production. Certain species are produced on an industrial scale for the production of antibiotics (e.g. penicillin) or for insertion in food (e.g. cheese). In the present work, three Penicillium species, part of the natural mycobiota growing on various food products were selected – P. ochrochloron, P. funiculosum and P. verrucosum var. cyclopium. The objective of our study was to value these species from the point of view of production of bioactive metabolites. The species were obtained after inoculation and growth in Czapek and Malt media. Both mycelia and culture media were analyzed to monitor the production of different metabolites by each fungus and their release to the culture medium. The concentrations of sugars, organic acids, phenolic acids and tocopherols were determined. Antioxidant activity of the phenolic extracts was evaluated, as also the antimicrobial activity of phenolic acids, organic acids and tocopherols extracts. Rhamnose, xylose, fructose and trehalose were found in all the mycelia and culture media; the prevailing organic acids were oxalic and fumaric acids, and protocatechuic and p-hydroxybenzoic acids were the most common phenolic acids; γ-tocopherol was the most abundant vitamin E isoform. Generally, the phenolic extracts corresponding to the mycelia samples revealed higher antioxidant activity. Concerning the antimicrobial activity there were some fluctuations, however all the studied species revealed activity against the tested strains. Therefore, the in-vitro bioprocesses can be an alternative for the production of bioactive metabolites that can be used by pharmaceutical industry.     

SDN Based Mobile Networks: Concepts and Benefits

Mobile Internet traffic is expected to grow faster than the fixed Internet traffic in a near future. Since, today’s broadband networks are approaching theoretical limits in terms of spectral efficiency per link, mobile operators are compelled to seek for new solutions that will be able to accommodate the expected traffic growth and improve their position in the competitive market. Addressing those challenges with current inflexible, not scalable and complex architecture is very hard, if possible at all. Software defined networking (SDN) is a new networking architecture paradigm that holds great promise to overcome many of mentioned limitations and provides required improvements in performance by decoupling control functions from underlying physical infrastructure. In this paper, we explain key reasons for transition to SDN based mobile networks and briefly describe several proposals of design scenario. Special emphasis is placed on SDN’s contribution to more efficient inter-cell interference management, traffic control and network virtualization.     

On adaptive refinement for boundary integral methods inelectrostatics

Numerical techniques based upon boundary integral methods like charge simulation or Galerkin boundary elements are still warmly received in the HV community because they are relatively easy to implement and use, and because they are accurate. However, the results can be sensitive to the quality of the discretization. In this work we introduce an efficient refinement scheme that automatically chooses the sections of conducting and dielectric boundaries where new nodes should be placed. The numerical results compare favorably to canonical solutions, and the method is shown to be effective on more complicated practical geometries     

Preliminary investigation of possible low-temperature fusion

Preliminary tests have been made with electrolytic cells utilizing 0.2N LiOD in D₂O as the electrolyte and a palladium cathode surrounded by a wire-wound platinum anode operating at cathode current densities of 100–400 mA/cm². The cathodes were swaged to diameters of 2.8 or 5.5 mm with 8.5 cm of active length. The electrolyte temperature was controlled, heat was removed by flowing water in a cooling jacket, and the cell was insulated. Cooling water and electrolyte temperatures were measured by thermocouples, and neutron and gamma-ray spectra were recorded. The electrolyte level was periodically monitored and replenished with D₂O. Tests up to 2 weeks in duration were made with no sustained release of energy in excess of the electrical power input, although there was one period of 12 h when an unaccountable heat excess was observed. In another test, an anomalous neutron flux was measured during the first few hours that was 3.5 standard deviations above the background.     

Investigation of tungsten carbide supported Pd or Pt as anode catalysts for PEM fuel cells

In this contribution, we present results of electrochemical characterization of prepared tungsten carbide supported palladium and platinum and Vulcan XC-72 supported palladium. These catalysts were employed as anode catalysts in PEMFC and results are compared to commercial platinum catalyst. Platinum seems to be irreplaceable as a proton exchange membrane fuel cell (PEMFC) catalyst for both the anode and the cathode, yet the high price and limited natural resources are holding back the commercialization of the PEMFCs. Tungsten carbide is recognized as promising catalyst support having the best conductivity among interstitial carbides. Higher natural resources and significantly lower price make palladium good candidate for replacement of the platinum catalyst. The presented results show that all prepared catalysts are very active for the hydrogen oxidation reaction. Linear sweep voltammetry curves of Pd/C and Pd/WC show existence of peaks at 0.07 V vs. RHE, which is assigned to absorbed hydrogen. H₂|Pd/WC|Nafion117|Pt/C|O₂ fuel cell has almost the same efficiency and similar power output as commercial platinum catalyst.     

The influence of thin benzoate-doped polyaniline coatings on corrosion protection of mild steel in different environments

The corrosion process of mild steel in the presence of benzoate-doped polyaniline coatings exposed to different environments (3% NaCl, atmosphere, and the Sahara sand) has been investigated. This system was also tested for cathodic protection and it has proven more efficient comparing to mild steel alone. Possible mechanisms of the corrosion protection of mild steel in the presence of a polyaniline-based coating in different corrosion media were also proposed.     

UV light copolymerization of dimethyl vinylphosphonate with bisphenol A ethoxylate dimethacrylate

Dimethyl vinylphosphonate (DMVP), a very promising monomer, was copolymerized with acrylic monomer bisphenol A ethoxylate dimethacrylate (BEMA), in different molar ratios, by radical photoinitiated polymerization in the presence of photoinitiator Darocur 4265 (3 wt%) and in the absence of solvent. The UV light polymerization was an efficient method to obtain polymers in a green procedure. The molar ratio between DMVP and acrylic monomer BEMA varied between 1:1 and 5:1. The copolymers were characterized by FTIR, thermal analysis, water uptake and conductivity. From the ATR-FTIR spectra of DMVP-BEMA copolymers at the molar ratios of 1:1–5:1, it was observed that the intensity of P-O-C aliphatic band increased with increases in DMVP content. The synthesized copolymers showed good thermal stability in the range of 335–390 °C. DMVP:BEMA copolymer at 1:1 molar ratio displayed the highest stability, with decomposition temperature above 390 °C, the highest temperature in the series. The water uptake decreased with increases in DMVP content and this behavior was correlated with the ionic conductivity. Based on the Bode diagrams, the ionic conductivity of DMVP:BEMA of 1:1 molar ratio was 6.15 × 10^?8 S cm^?1 and that of DMVP:BEMA of 2:1 molar ratio was 3.69 × 10^?8 S cm^?1 which were considered promising as valuable conducting materials.     

Molecular diversity among natural populations of <Emphasis Type="Italic">Lactobacillus paracasei</Emphasis> and <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis>/<Emphasis Type="Italic">paraplantarum</Emphasis> strains isolated from autochthonous dairy products

The diversity of 87 Lactobacillus paracasei and Lactobacillus plantarum/paraplantarum strains, previously identified from different autochthonous dairy products, was investigated by phenotypic and genotypic approaches. The increased resolution obtained using phenotypic and genotypic characterization allowed the level of strain heterogeneity detection to be widened. Phenotypic diversity was evaluated by studying biochemical characteristics of technological interest, including antimicrobial and proteinase activities, resistance to nisin, aggregation ability, production of exopolysaccharides, acetoin and diacetyl, citrate utilization, and antibiotic susceptibility. Genotypic diversity was generally evaluated by PCR amplification of repetitive bacterial DNA element fingerprinting using the (GTG)₅ primer [(GTG)₅-PCR]. Moreover, in cases where strains were not discriminated by (GTG)₅-PCR combined with phenotypic analysis, pulsed-field gel electrophoresis (PFGE) analysis was performed. The results indicate that L. plantarum/paraplantarum and L. paracasei natural isolates from artisanal dairy products are a gold mine in terms of diversity of strains and could be potentially interesting to dairy companies for the formulation of functional starter cultures in the production of innovative foods.