Suchergebnisse

Silicon (Si) is an element necessary for the proper functioning of the body. It affects cell viability, osteoblast differentiation, blood vessel elasticity, type I collagen synthesis, as well as the condition of the skin, hair, and nails. It is also considered an antiatherosclerotic agent. The silicon content in the human body is 6 – 7 g, and the only absorbable form is orthosilicic acid. The average daily requirement of the body for this element is in the range of 20 to 40 mg, whose diet does not fully provide. In addition, the silicon content in the body decreases with age, so there is a need for its supplementation.
There are many liquid, gel, and spray diet supplements available that vary in concentration and silicon compound. The aim of the research was to determine the content of orthosilicic acid in liquid diet supplements. Thirteen preparations were selected for the study, in which concentration of available silicon was determined by a spectrophotometric method. This method was based on reaction in the acidic environment of dissociated silicon with ammonium molybdate.
Among the selected products, the highest concentration of available silicon form was obtained for pharmaceuticals composed of choline stabilized orthosilicic acid, which is in the range of 50-2000 ppm. However, its concentration in preparations containing monomethylsilanetriol (MMST) did not exceed 50 ppm.
Keywords: chemical sciences, orthosilicic acid, Uv-Vis spectroscopy

The size and shape of biological particles are important parameters allowing discrimination between various species. We have studied several aerosols of biological origin such as pollens, bacterial spores and vegetative bacteria. All of them presented different morphology. Using optical size and shape analyser we found good correlation between light scattering properties and actual particle features determined by scanning electron and fluorescence microscopy. In this study, we demonstrated that HCA (Hierarchical Cluster Analysis) offers fast and continuous bioaerosol classification based on shape and size data matrices of aerosols. The HCA gives an unequivocal interpretation of particle size vs. asymmetry data. Therefore, it may provide high throughput and reliable screening and classification of bioaerosols using scattering characteristics. Keywords: bioaerosol classification, scattering, particle size and shape analysis, biological warfare agents' detection, hierarchical cluster analysis (HCA)