Safety assessment and antimicrobial properties of the lactic acid bacteria strains isolated from polish raw fermented meat products

Twenty-one strains of the genus Lactobacillus and the genus Pediococcus, isolated from Polish raw fermented meat products, were examined for the potential probiotic properties: resistance to simulated gastric and intestine conditions, safety assessment, and antimicrobial properties. Strains were resistant to gastric enzymes and low pH (3–6 log CFU/mL decrease) and intestinal enzymes and bile salts (1–3 log CFU/mL decrease). Most strains were resistant to gentamycin, streptomycin, vancomycin, tetracycline, ciprofloxacin, and kanamycin. Three of them (Lb. brevis BAL1, BAL10, and KL5) produced β-glucuronidase, which excludes them from qualifying as safe. Seven strains had the ability to produce bacteriocins or bacteriocin-like substances. Overall, strains Lb. brevis SCH6, Pd. pentosaceus BAL6, and KL14 revealed selected superior characteristics (resistance to the gastrointestinal conditions, safety assessment, and antimicrobial properties) as compared to the other LAB strains investigated, which made them a viable bioprotective culture that can be inoculated in raw fermented meat products as starter cultures.     

Analysis of electromigration phenomenon in thick-film and LTCC structures at elevated temperature

Studies on electromigration phenomenon in thick-film structures on alumina and LTCC substrates are presented in this paper. The effects of storage of Au and Ag electrode patterns in temperature range up to 300 °C under voltage bias were examined. The leakage characteristics of electrodes with 100 μm spacing at 50 V dc bias as a function of time and temperature are presented and analyzed. Scanning electron microscope (SEM) equipped with the energy-dispersive X-ray spectroscopy (EDX) detector was applied for determination of metal ions transport. Test structures with Au-based conductive material are much more resistant to electromigration than Ag-based layers.     

Thermal Expansion,Electrical Resistivity,and Spreading Area of Sn-Zn-In Alloys

Thermal expansion and electrical resistivity of alloys based on Sn-Zn eutectic with 0.5, 1.0, 1.5, and 4.0 wt.% additions of In were studied. Thermal expansion measurements were performed using thermomechanical analysis tester over 223-373 K temperature range. Electrical resistivity measurements were performed with four-probe method over 298-423 K temperature range. The electrical resistivity of alloys increases linearly with temperature and concentration of In; also coefficient of thermal expansion of the studied alloys increases with In concentration. Scanning electron microscopy revealed simple eutectic microstructure with In dissolved in Sn-rich matrix. The results obtained were compared with the available literature data. Spreading tests on Cu of Sn-8.8Zn alloys with 0.5, 1.0, and 1.5 at.% of In were performed. Wetting tests were performed at 250 °C, by sessile drop method, by means of flux, and wetting times were 3, 8, 15, 30, and 60 min. In general, no clear effect of wetting time on spreading was observed.     

The comparative analysis of standards used in Poland for trenchless rehabilitation of sewage pipes and the problems in design of resin liners

The paper presents not only the comparative analysis of the three standards (German, Danish and American) commonly used in Poland for the design of resin liners, but also the chosen problems involved with the design. The attached examples of calculations give a chance to investigate the influence of noticed differences in basic assumptions on the final results including the minimum, acceptable wall thickness of the linings used for trenchless renovation of gravitational sewers.     

Review: tailoring the properties of macroporous carbon foams

Carbon foams are non-toxic, highly porous, light materials which demonstrate a wide range of properties. That fact allows carbon foams to be applied in many areas of life, ranging from electronics industry, through machinery, car and construction industry, to environmental protection. The properties of carbon foams are closely connected with their density, and its value is especially influenced by their internal structure, i.e. mainly size and number of pores, pore wall thickness and structural order of solid matrix. That is why it is possible to design the properties of carbon foams by controlling their growth. The main control factors are selecting the suitable raw material, the process parameters (temperature and pressure) and the suitable production method. Additionally, the properties of carbon foams may be modified by doping them with carbon or mineral fillers. The second method is the enrichment of carbon matrix with heteroatoms, mainly of boron and nitrogen. This paper presents the review of the possibilities of tailoring the structure and properties of carbon foams, based on the current level of knowledge available in the literature.     

Laboratory tests of filtration coefficient of selected materials used in liquidating shafts in collieries

There are a lot of dangers associated with closing mine shafts which may emerge during its liquidation works, and after liquidation of a shaft. The most important of them are: methane hazard, water hazard, and public safety hazard, which are commonly connected with occurrence of sinkholes. In the process of shaft liquidation it is extremely important to choose the right backfill materials, which determine stability of the backfill column and proper drainage of the backfill, which will match or exceed potential flow of water into a shaft. When the water flows into a liquidated shaft the main problem is a change in permeability coefficient of the used backfill materials due to grain degradation resulting from the fall into a shaft and the pressure within the backfill column. The article presents results of laboratory tests on the influence of vertical pressure on filtration coefficient and compressibility of the most commonly used backfill materials. During the tests, samples of the materials were loaded in a hydraulic press, simulating in this way the increase in vertical pressure within the backfill column. Compressibility of a given material and the change in filtration coefficient were assessed.     

Modification of Fe and Al elemental powders’ sintering with addition of magnesium and magnesium hydride

An attempt to modify sintering of iron and aluminium elemental powders with use of small additions of Mg and MgH₂ was presented in this paper. The kinetics of such modified sintering was investigated using DSC technique, XRD analysis and SEM observations. Significant changes in the mechanism of exothermal formation reaction of Fe–Al intermetallic phases in compositions doped with magnesium and its hydride was observed. Initiation temperature of Self-propagating High-temperature Synthesis (SHS) reaction was pronouncedly shifted to lower value as compared with undoped composition. Influence of additions on the SHS reaction kinetics parameters was also calculated with use of the JMA model and changes of the Avrami exponent value of specific phase formation was noticed. Positive effect of MgH₂ addition on partial homogeneity of final product was also studied.     

Fatty acid composition of egg yolk phospholipid fractions following feed supplementation of Lohmann Brown hens with humic-fat preparations

The effect of feed supplementation with humic-fat preparations on the fatty acid composition of egg yolk phospholipid fractions was studied. The Lohmann Brown was the experimental hen strain and two feeding mixtures were applied – the standard feed and the mixture supplemented with humic-fat preparations. The fatty acid profile of yolk lipids was significantly affected (P = .05) by the supplementation of feed and total increase of n-3 polyunsaturated fatty acids (PUFA) was established. A different distribution of n-3 PUFA in egg yolk lipid fractions was observed: α-linolenic acid (18:3) was found in the triacylglycerol fraction, whereas docosahexaenoic acid (22:6) was detected in the phospholipid fractions. Supplementation of the hen’s diet with humic-fat preparations resulted in the production of n-3 enriched eggs with decreased n-6/n-3 ratio in all phospholipid fractions in comparison to the eggs from the control group.