A laboratory simulation of acid rain was performed in which soil monoliths from the Wielkopolski National Park area were sprinkled with water solutions of sulphuric acid of pH 3.0 or 2.0, and for reference with distilled water of pH 5.6. The form and amount of the washed out aluminium as well as changes in the chemical properties of the soil studied were determined. The process of aluminium release proved particularly dangerous for acidic or slightly acidic soils which cover a large part of the National Park area.
Lysozyme (EC 3.2.1.17, mucopeptyde N-acetylmuramic-hydrolase) exhibits the ability to destroy cell walls of Gram-positive bacteria. The range of activity for this enzyme may be extended through modifications, as a result of which polymerized forms of lysozyme are obtained. It was found that lysozyme dimer exhibits bacteriostatic properties towards both Gram-positive and Gram-negative bacteria. The aim of the study was to determine the conditions of thermal modification of lysozyme and to assess the antibacterial action of this enzyme after modification. The dimer content in the modified lysozyme preparations depended on the pH and concentration of a given solution. It was found that modified lysozyme was characterized by higher antibacterial activity towards Micrococcus luteus and Escherichia coli in comparison to the unmodified form of the enzyme.
The purpose of this study was to evaluate transepidermal water loss, skin hydration and skin pH in normal ponies. Sixteen ponies of both sexes were examined in the study. Measurements were taken from seven different sites: the neck region, the shoulder, thorax, lumbar, inguinal, lip region and the auricle. In each of the regions transepidermal water loss (TEWL), skin hydration and skin pH were measured. For transepidermal water loss, the lowest values were observed in the lumbar region (9.71g/hm2), while the highest values were observed in the lip region (22.35 g/hm2). In the case of skin hydration the lowest values were observed for the thorax region (2.13 CU), and the highest for the lip region (41.81 CU). For skin pH, the lowest results were obtained in the lumbar region (6.93), and the highest in the lip region (7.96).
Our objective was to evaluate the influence of pH values on the microcoagulation process of whey protein concentrate and whey protein isolate, and obtaining a solid fat mimetics. Such substances were obtained in a precise pH condition. Differences in pH values at which fat mimetics can be obtained are caused by differences in composition of the WPC and the WPI, and particularly, by different lactose content. Protein in the WPC with high a content of lactose was more resistant to denaturation. At pH >3.3 for the WPI 200 g protein/kg dispersion and at pH >3.7 for the WPC 220 g protein/kg dispersion, a decrease in the stability of whey protein structure was observed. Light and transmission electron micrographs show, that at pH lower than mentioned above, microcoagulates are composed of small particles (several micrometers). Aggregation is probably restricted due to electrostatic repulsions of positively charged protein molecules.
For the period of 4 years, in quarter-time cycle, samples had been taken from surface microlayers and subsurface water of the lakes: Gardno, Jasień and Dołgie Wielkie, by two techniques (Garret net and glass plate). In each talked over layers we have analyzed contents of calcium, general alka-linity, conductance and water reaction (pH). We have also determined the ability of surface mi-crolayer to accumulate these components and we have compared it to subsurface water ability and verified whether this ability depends on the kind of the lake.
Porcine and bovine semimembranosus muscles were examined after, respectively, 24 h and 96 h from slaughter. The muscles were pressurised at 200, 300 and 400 MPa for 10 min. The pH value, pressure-induced drip, ability to hold free- and added water, and thermal drip were analysed. The pH values for muscles were found to increase with pressure. Pressurization at 200 MPa caused the greatest drip of meat juice. The ability to hold free water was dependent on muscle and pressure. The pressure of 200 MPa gently lowered this quality for porcine muscle and improved it for bovine muscle. Higher pressures significantly improved the water- holding capacity. Different tendency was observed for the ability to hold added water that decreased with pressure for porcine and bovine muscles, having the lowest values at 400 MPa. All high pressure values applied decreased the drip from the muscles during cooking.