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Carbon nitride (\CNx) films, deposited by pulsed laser deposition (PLD) in nitrogen (\N2) atmosphere, were studied with respect to mechanical, morphological, compositional, structural, and optical properties. All the samples were prepared at room temperature and under various \N2 pressures, ranging from vacuum up to 50 Pa. Nitrogen concentration ( \CN) rapidly increases with increasing \N2 pressure and reaches to a saturated value above 10 Pa. The Raman results reveal that the D/\G ratio increases with the increase in \N2 pressure, contributing the graphitization of carbon films. With further addition of nitrogen into carbon films, optical transmission is enhanced. Localization of the \pi electrons due to the heteropolar bonding and the high porosity of the \CNx samples are speculated to be the reason of enhancement in optical transmission. [ABSTRACT FROM PUBLISHER]

Abstract: The effects of extracellular polymeric substances on aerobic granulation in sequencing batch reactors were investigated by evaluating the content and compositions of extracellular polymeric substances, and the relationship between extracellular polymeric substances composition and surface properties of glucose-fed aerobic granules. The results showed that extracellular polymeric substances could affect surface properties of cells, such as surface charge and hydrophobicity, enhance polymeric interaction and promote aerobic granulation. Moreover, extracellular polymeric substances were produced mainly in the exponential phase, and served as carbon and energy source in starvation phase during granulation process, thus regulating the growth of bacteria in the interior and exterior of granules, and maintaining the integrality of granules. [Copyright &y& Elsevier]

Presents evidence from carbon isotope measurements for biological origins of individual long-chain n-alkanes in sediments from Nansha Sea, China. Carbon isotopic composition and genetic feature of the long-chain n-alkanes; Calculation of the fractional contributions of the two end member sources to individual n-alkanes.

A new kind of convenient, low-cost, environmentally friendly, and simple one step synthetic route for the preparation of C-dots-based CDs (CA + Phen) fluorescent turn-off probe for Fe 2+ and Fe 3+ from 1,10-phenanthroline (Phen) using anhydrous citric acid (CA) as the sole precursor without any solvents by solid state method. Only the Fe 2+ and Fe 3+ can readily quench the fluorescence of the CDs (CA + Phen), indicating a remarkably high selectivity towards Fe 2+ and Fe 3+ over other metals with a detection limit as low as 20 nM and 35 nM. The CDs (CA + Phen) exhibited a low cytotoxicity and could label the HK-2 cells. Additionally, this CDs (CA + Phen) has been successfully applied for the determination of Fe in real sample of milk. Endowed with relatively high sensitivity and selectivity, the present sensor holds the potential to be applied for the detection of Fe 2+ and Fe 3+ in aqueous media. [ABSTRACT FROM AUTHOR]