The assembly of (Z)-chloro-exo-methylenetetrahydrofurans by an original and connective anionic cascade sequence is reported. Base-catalysed condensation of β-hydroxyketones with 1,1-dichloroethylene generates, in moderate to good yields, the corresponding (Z)-chloro-exo-methylenetetrahydrofurans. Acidic treatment of this motif leads to several unexpected dimers, possessing unique structural fea...

Two models of candidates for hereditary symmetry operators are proposed and thus many nonlinear systems of evolution equations possessing infinitely many commutative symmetries may be generated. Some concrete structures of hereditary symmetry operators are carefully analyzed on the base of the resulting general conditions and several corresponding nonlinear systems are explicitly given out as i...

In this work we consider a certain class of Volterra integral equations possessing an infinite set of solutions. We investigate the application of Euler’s method together with the use of extrapolation procedures. Several examples are considered illustrating our results as well as the use of graded meshes and the application of higher order methods. keywords Volterra integral equations; weakly s...

A rapidly increasing number of chemicals, or their degradation products, are being recognized as possessing estrogenic activity, albeit usually weak. We have found that effluent from sewage treatment works contains a chemical, or mixture of chemicals, that induces vitellogenin synthesis in male fish maintained in the effluent, thus indicating that the effluent is estrogenic. The effect was extr...

Analysis of data from 280 rivers discharging to the ocean indicates that sediment loadslyields are a log-linear function of basin area and maximum elevation of the river basin. Other factors controlling sediment discharge (e.g., climate, runoff) appear to have secondary importance. A notable exception is the influence of human activity, climate, and geology on the rivers draining southern Asia ...

Macrophyta are the initial link introducing toxic mercury to the trophic chain. Research was carried out at 24 stations located within the Polish coastal zone of the Southern Baltic, in the years 2006-2012. Fifteen taxa were collected, belonging to four phyla: green algae (Chlorophyta), brown algae (Phaeophyta), red algae (Rhodophyta) and flowering vascular plants (Angiospermophyta), and total ...

The synthesis, in vitro evaluation, and conformational study of a new series of small-size peptides acting as antifungal agents are reported. In a first step of our study we performed a conformational analysis using Molecular Mechanics calculations. The electronic study was carried out using Molecular electrostatic potentials (MEPs) obtained from RHF/6-31G calculations. On the basis of the theo...

Propofol is a short-acting intravenous anaesthetic agent and widely used not only in operating rooms but also in the intensive care unit (ICU). Apart from its multiple anaesthetic advantages, the neuroprotective effect of propofol has been demonstrated in diverse models of neuronal injury. The effect of propofol results from activation of gamma-aminobutyric acid (GABA) receptor, modulation exci...

A method for the analysis of 10 perfluorinated compounds (PFCs) in whole fish homogenate is presented and applied to 60 fish samples collected from the Ohio, Missouri, and upper Mississippi Rivers in 2005. Method accuracy ranged between 86 and 125% with limits of quantitation between 0.2 and 10 ng/g wet weight. Intra- and inter-batch precision was generally +/-20%. Perfluorooctane sulfonate (PF...

Whittingtonocotyle n. gen. is proposed for species with a male copulatory organ sclerotized, spiral, clockwise, non-articulated to the accessory piece; prostatic reservoir separated into two/three zones with one or two terminal areas densely stained; vaginal opening dextrodorsal; anchors without well-defined roots; and dorsal bar with anteromedial protuberance. Two new species of Whittingtonoco...