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The study focused on litter processing efficiency of the sesarmid crab, Parasesarma plicatum under experimental conditions and its possible role in carbon structuring in the mangrove habitats. The feeding experiment of crab with different stages of leaves of diverse mangrove species revealed that senescent brown leaves were preferred the most, due to their lesser tannin content. The leaf consumption differed significantly with leaf state as well as mangrove species and highest was for Avicennia officinalis brown leaves. The ingestion-egestion assay of P. plicatum revealed that it assimilated an average of 65.75 ± 10.30% of mangrove litter. The experimental study also revealed that rather than already reported C/N ratio, the inhibiting factors such as tannin and lignin like substances control the palatability of leaves by the crab species. The analysis of carbon and nitrogen variants in the experimental water indicated that handling of leaves by the crab helps in leaching of nutrients to the substratum. Therefore, the findings of litter processing efficiency of this sesarmid crab from the present study highlights its significance in structuring the carbon in natural mangrove habitat. [ABSTRACT FROM AUTHOR]

The species composition, abundance, biomass, and distribution of zooplankton were studied on the shelf and slope of the northwestern Laptev Sea and the shelf of the East Siberian Sea in summer 2015. The trophic status of common zooplankton and fish species, as well as their position in the food webs of these two seas, has been determined based on stable carbon and nitrogen isotope analyses (δ13C and δ15N). Data of both stomach content and stable isotope analyses show significant age-related variations in the trophic status of the Arctic cod Boreogadus saida, which is the dominant fish species. [ABSTRACT FROM AUTHOR]

Nanoscale composite materials based on titanium dioxide, sulphur, and carbons were obtained. The samples were characterized using X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller and Barret–Joiner–Halenda methods, electron paramagnetic resonance spectroscopy, and ultraviolet–visible and infrared spectroscopy. X-ray powder diffraction revealed the phase of anatase in all composites and appearance of rutile phase for samples with high sulphur content. It was established that composites consist of nanoparticles ca. 6–10 nm. Analysis of nitrogen adsorption–desorption isotherms for the synthesized samples showed the presence of a hysteresis loop which is the evidence for mesoporous structure of the powders. Absorption spectra of nanocomposites showed a bathochromic shift compared with the absorption band of pure TiO2. It was found that modification of titanium dioxide with sulphur and carbons leads to bandgap narrowing of composites. Nanocomposite samples showed higher photocatalytic activity in the destruction of safranin T under ultraviolet and visible irradiation compared to pure titanium dioxide. It can be connected with the participation of additives in the inhibition of electron–hole recombination, prolongation of charges lifetime, increasing of efficiency of interfacial charge separation, and formation of doping electronic states. [ABSTRACT FROM AUTHOR]

The major and minor constituents of cholesterol gallstones were investigated by Laser-induced breakdown spectroscopy. The elements detected in the center and in the shell part were calcium (Ca), carbon (C), copper (Cu), hydrogen (H), magnesium (Mg), nitrogen (N), sodium (Na), oxygen (O) and potassium (K), but Cu was absent from the surface of the cholesterol gallstones. Our experimental results revealed that calcium was a major constituent of cholesterol gallstones. Our results also showed that the concentration of Ca, Cu and Mg were large in the center in comparison with the shell. Laser-induced breakdown (LIB) spectra of both portions of the surface (colored part and discolored part) of the cholesterol gallstones were recorded. The concentrations of sodium and potassium were higher in the non-pigmented (colored) part than in the pigmented part (discolored/pigment), which showed that the deficiency of sodium and potassium was playing a key role in the formation of discoloration at the different locations on the outer surfaces of the cholesterol gallstones. Thus, laser-induced breakdown spectroscopy (LIBS) is a suitable technique for the analysis of cholesterol gallstones without any sample preparation. [ABSTRACT FROM AUTHOR]