High exposure to arsenic from drinking water at several localities in eastern Croatia

This study investigated the relationship between arsenic concentrations in drinking water in four towns/villages in eastern Croatia and corresponding hair arsenic concentrations of residents. The mean arsenic concentrations in community drinking water samples were 0.14, 37.88, 171.60, and 611.89 microg/l. The corresponding mean concentrations of the element in hair samples of subjects residing in each of the localities were 0.07 (n=11), 0.26 (n=17), 1.74 (n=11), and 4.31 microg/g (n=23). Chronic exposures to arsenic levels estimated in three investigated locations could present a serious health threat to around 3% of Croatian population.     

Transparent exopolymeric particles' distribution in the northern Adriatic and their relation to microphytoplankton biomass and composition

Transparent exopolymer particles (TEP) are generated during transformation processes within the non-living organic matter continuum in the seawater. Seasonal dynamics of TEP along the Po River Delta-Rovinj transect was followed during the 3-year period, using a spectrophotometric method of determination of TEP. Relationships between TEP and phytoplankton biomass (chlorophyll a), abundance and composition, as well as phaeophytin, were analysed. Microphytoplankton spring blooms are confirmed to be an important source of TEP, with some species more related to TEP concentration dynamics, such as Chaetoceros sp. and Skeletonema costatum. Notable spatial west to east gradient of autotrophic biomass and consequently of TEP was observed, as well as gradual decrease with depth. In addition, TEP concentration increments were observed up to 2 months before the mucilage events followed by the decrease of TEP concentration during the event itself. Pattern of TEP dynamics in the years with mucilage events was the most pronounced in 2002, when the event was spatially and temporally the most extended.     

Performance degradation of decision-directed c.p.s.k. demodulator due to uncompensated time delay of decision circuitry

The influence of the uncompensated time delay incurred in the nonoptimum symbol decision filter on the error performance of a decision-directed c.p.s.k. demodulator is considered. An iterative method for the probability of bit error computation is used.     

Reflectance of macerals from bright brown coal,Pernik basin

Reflectance of macerals from Palaeogene brown coal from the Pernik basin in Bulgaria was determined using an ‘Opton’ microscope-photometer. Depending on the nature of the original plant material and on the degree of biochemical alteration, the maceral reflectance increases from the group of liptinite (R_O (%) = 0.06–0.28) towards the group of huminite (R_O (%) = 0.29–0.52) and the group of inertinite (R_O (%) = 0.84–3.05). The action of geochemical factors did not result in obliteration of the differences in the reflectance of macerals from the huminite group.     

Copolymerization of polyurethane macromer with 2-hydroxyethyl methacrylate: NMR kinetic study

Summary The copolymerization kinetics of Polyurethane containing a vinylic bond with 2-hydroxyethyl methacrylate in solution was investigated. The reaction was studied using a JEOL-PS-100 spectrometer at various temperatures and concentration conditions. The a and b exponents in the equation for the overall polymerization rate, R_p=const[M]^a[I]^b were determined. The reaction products were analyzed by means of ¹H-NMR and turbidimetric titration.