In this study, the synthesis, structure and physical properties of two series of thermoplastic polyurethanes based on hydroxypropyl-terminated poly-(dimethylsiloxane) (HP-PDMS) or hydroxyethoxypropyl-terminated poly-(dimethylsiloxane) (EO-PDMS) as soft segments, and 4,4′-methylenediphenyl diisocyanate and 1,4-butanediol as hard segments were investigated. The polyurethanes were synthesized by two-step polyaddition in solution. The effects of the type and content of PDMS segments on the structure, thermal and surface properties of copolymers were studied by 1 H-, 13 C-nuclear magnetic resonance (NMR) spectroscopy and two-dimensional NMR spectroscopies (heteronuclear multiple bond correlation (HMBC) and rotating-frame nuclear Overhauser effect (ROESY)), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide-angle X-ray scattering (WAXS), scanning electron microscopy (SEM) and water contact angle and water absorption measurements. Thermal properties investigated by DSC indicated that the presence of soft PDMS segments lowers the glass transition and melting temperatures of the hard phase as well as the degree of crystallinity. SEM analysis of the copolymers with a lower soft segment content confirmed the presence of spherulite superstructures, which arise from the crystallization of the hard segments. When compared with polyurethanes prepared from HP-PDMS, the copolymers synthesized from EO-PDMS with the same content of the soft segments had a higher degree of crystallinity, better thermal stability and a less hydrophobic surface. The obtained results showed that the synthesized polyurethanes had good thermal and surface

Lactate dehydrogenase (LDH) and lactate are some of the hypoxy biochemical parameters. Extracellular activity of this enzyme increases under the condition of oxidative stress, since the cell integrity can be disrupted during the lipid peroxidation process. Subsequently that leads to the increase level of the lactic acid and lactic acid salts. The objective of this investigation is establishing the level of LDH, LDH1 (HBDH) and the lactate concentration in aqueous humour in patients with primary open-angle glaucoma. Biochemical analysis have been made by enzymatic-colometric method (lactate) and UV-kinetic method (LDH and HBDH) in aqueous humour of 30 patients (42 eyes) with primary open-angle glaucoma (POAG) and 30 patients (40 eyes) with cataract (the control group). The increased values of lactate and the activity of LDH and HBDH enzyme in aqueous humour of POAG patients in correlation with the control group are the results not only of oxidative stress but also of hypoxy and the mitochondry oxidative function (p<0,001). The increased activity of the examined biochemical parameters in the aqueous humour of the POAG patients points to the fact that other mechanisms, besides IOP, have a role in glaucoma pathogenesis.

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Entrepreneurs are playing a major role in the economy of each country on the planet. They contribute to national economies by starting up and running small and medium sized enterprises (SMEs), which make more than 95% of the total number of enterprises and which are providing jobs to more than 60% of all employees within each country. The significance of entrepreneurship for economic development oblige goverments and all other relevant institutions within each country to continue to facilitate its growth by all means necessary. In order to do this, these institutions need to be familiar with motives of entrepreneurs to start their own business. In this paper, results of empirical research concerning motivational factors of entrepreneurs in Serbia are presented. This research presents a continuation of serie of research on this topic which were conducted in several countries, by using the same methodological approach.

The results indicate that mutant GSTO2*Asp genotype is associated with increased risk of age-related cataract in smokers and ultraviolet-exposed subjects, suggesting a role of inefficient ascorbate regeneration in cataract development.