Vitamin D Status in Central Europe

Little published information is available regarding epidemiological data on vitamin D status in the large geographical region of Central Europe (CE). We searched the journal literature with regard to 25(OH)D concentrations among community-dwelling or healthy people living in CE. 25(OH)D concentrations varied by age, season, study sample size, and methodological approach [i.e., 25(OH)D assay used]. Concentrations of 25(OH)D in CE appeared lower than 30 ng/mL, and the magnitude of hypovitaminosis D was similar to that reported in Western Europe. While most of the studies reviewed were cross-sectional studies, a longitudinal study was also included to obtain information on seasonal variability. The longitudinal study reported wintertime 25(OH)D values close to 21-23 ng/mL for all studied age groups, with a significant increase of 25(OH)D in August reaching 42 ng/mL for those aged 0-9 years, but only 21 ng/mL for the elderly aged 80-89 years. The decrease in 25(OH)D with respect to age was attributed to decreased time spent in the sun and decreased vitamin D production efficiency. Based on the literature review on vitamin D status in the CE populations, it can be concluded that 25(OH)vitamin D levels are on average below the 30 ng/mL level

Photoreactive acrylics pressure-sensitive adhesives

Pressure-sensitive adhesives (PSAs) are non-metallic materials used to bond other materials, mainly on their surfaces through adhesion and cohesion. Adhesion and cohesion are phenomena, which may be described thermodynamically and chemically, but actually they cannot be measured precisely. It was shown that the most important bonding processes are bonding by adhesion and bonding with pressure- -sensitive adhesives. The difference between pressure-sensitive adhesives and other adhesives, such as contact adhesives, is in the permanent surface stickiness of the pressure-sensitive adhesives before, or after, the application. The fastest developing polymers departments are: initiating UV photopolymerization and photocrosslinking. Ultraviolet radiation (UV) part of the electromagnetic radiation having a wavelength of 100 to 400 nm, the practical use has an area of 200 to 400 nm. UV radiation does not cause visual impressions results in a strongly fluorescence, photoelectric, photochemical reactions and has a high biological activity. It is particularly important industrial use of UV crosslinking which is used in the manufacture of a wide range of self-adhesives, such as assembly lines, labels, decorative films, protective films, patches and biomedical electrode. Especially important critical point during UV-curing is the balance between adhesion and cohesion of the crosslinked pressure-sensitive adhesive layer. An important element is finding the appropriate beneficial relationship between tack, adhesion and cohesion of the crosslinked pressure-sensitive adhesives that offer assurance to their respective industrial applications. Ultraviolet radiation crosslinking is carried out at room temperature and does not require high temperatures, an important disadvantage pressure-sensitive adhesives crosslinked by heat. Compared to systems crosslinked thermally, the use of UV crosslinking process provides greater speed and effective a crosslinking process, and also does not damage the materials with low thermal resistance

Effect of 1-substituted imidazole derivatives for the curing process of epoxy- -isocyanate composition

The kinetics of the curing process of isocyanate-epoxy materials hardened in the presence of 1- substituted imidazole derivatives was studied by the Coast-Redfern method. The extent of a conversion parameter of the curing process in two ways was calculated: DSC (peak area integration) and rheology (viscosity changes). The activation energy values were determined for epoxy-isocyanate cured in the presence of 0.5; 1.0 and 2.0 phr 1-substituted imidazole derivatives respectively. Increasing of accelerators amount results in decreasing the activation energy and other kinetic parameters

Effect of 1-substituted imidazole derivatives for the curing process of epoxy- isocyanate composition

The kinetics of the curing process of isocyanate-epoxy materials hardened in the presence of 1- substituted imidazole derivatives was studied by the Coast-Redfern method. The extent of a conversion parameter of the curing process in two ways was calculated: DSC (peak area integration) and rheology (viscosity changes). The activation energy values were determined for epoxy-isocyanate cured in the presence of 0.5; 1.0 and 2.0 phr 1-substituted imidazole derivatives respectively. Increasing of accelerators amount results in decreasing the activation energy and other kinetic parameters

Wpływ nieprzereagowanych monomerów na wybrane właściwości poliakrylanowych klejów samoprzylepnych

Self-adhesive materials manufactured from acrylic polymers, especially acrylic pressure- sensitive adhesives (PSA) are widely used in different industrial applications. The wide ranges of self-adhesive products comprise self-adhesive tapes which are used for the mounting of composite plates in the furniture industry. The goal of the investigations was the synthesis of solvent-based acrylic PSA used as furniture tape and the testing of the influence of free residue monomers on their properties (tack, peel adhesion, shear strength, shrinkage). The best performance for self-adhesive tapes in the form of polymeric films with 30 g/m² and 60 g/m² coating weights and containing less than 0.3 wt.% residue monomers was observed.Materiały samoprzylepne wytworzone na bazie polimerów akrylanowych, w tym poliakrylanowekleje samoprzylepne (PSA) mają powszechne zastosowanie w przemyśle. Do szerokiej gamy materiałów samoprzylepnych zaliczamy taśmy samoprzylepne, stosowane przy montażu płyt kompozytowych w przemyśle meblarskim. Celem przedstawionych badań była synteza używanych w taśmach meblarskich rozpuszczalnikowych klejów samoprzylepnych na bazie poliakrylanów oraz zbadanie wpływu nieprzereagowanych monomerów na ich właściwości (kleistość, adhezja, wytrzymałość na ścinanie, skurcz). Najlepszymi właściwościami charakteryzowały się taśmy samoprzylepne w postaci filmów klejowych grubości 30g/m2 oraz 60g/m2, zawierających nie więcej niż 0.3% wagowych nieprzereagowanych monomerów