Characterizing the scent and chemical composition of Panthera leo marking fluid using solid-phase microextraction and multidimensional gas chromatography–mass spectrometry-olfactometry

Lions (Panthera leo) use chemical signaling to indicate health, reproductive status, and territorial ownership. To date, no study has reported on both scent and composition of marking fluid (MF) from P. leo. The objectives of this study were to: 1) develop a novel method for simultaneous chemical and scent identification of lion MF in its totality (urine + MF), 2) identify characteristic odorants responsible for the overall scent of MF as perceived by human panelists, and 3) compare the existing library of known odorous compounds characterized as eliciting behaviors in animals in order to understand potential functionality in lion behavior. Solid-phase microextraction and simultaneous chemical-sensory analyses with multidimensional gas-chromatography-mass spectrometry-olfactometry improved separating, isolating, and identifying mixed (MF, urine) compounds versus solvent-based extraction and chemical analyses. 2,5-Dimethylpyrazine, 4-methylphenol, and 3-methylcyclopentanone were isolated and identified as the compounds responsible for the characteristic odor of lion MF. Twenty-eight volatile organic compounds (VOCs) emitted from MF were identified, adding a new list of compounds previously unidentified in lion urine. New chemicals were identified in nine compound groups: ketones, aldehydes, amines, alcohols, aromatics, sulfur-containing compounds, phenyls, phenols, and volatile fatty acids. Twenty-three VOCs are known semiochemicals that are implicated in attraction, reproduction, and alarm-signaling behaviors in other species

Evaluating spinel ferrites MFe 2 O 4 (M = Cu, Mg, Zn) as photoanodes for solar water oxidation: prospects and limitations

International audienceThe search for ideal semiconductors for photoelectrochemical solar fuel conversion has recently recognized the spinel ferrites as promising candidates due to their optoelectronic tunability together with superb chemical stability

Semiconducting alternating multi-block copolymers via a di-functionalized macromonomer approach

The development of fully-conjugated semiconducting block-copolymers is an important goal for organic electronics, but to date has been almost exclusively limited to materials containing poly(3-alkylthiophenes). Here we present the prototype of a class of fully-conjugated semiconducting block copolymers (prepared using a versatile route based on conjugated macromonomers and a cross-coupling polycondensation) that exhibit hole mobility in field effect transistors of the order of 0.1 cm(2) V-1 s(-1) and nanoscopic phase domain separation

Evaluating Charge Carrier Transport and Surface States in CuFeO2 Photocathodes

Interest in delafossite (CuFeO2) as a candidate p-type photocathode for photoelectrochemical (PEC) solar fuel production has recently been increasing, mainly due to its excellent stability in aqueous environments and favorable light absorption properties. However, its PEC performance has remained poor for reasons that have not yet been specifically determined. Herein, we report a detailed investigation on sol-gel-processed CuFeO2 with a range of spectroscopic, PEC, and microscopy techniques aimed at unraveling the material properties governing photogenerated charge carrier harvesting in this v. An analysis of the bulk transport properties using microwave conductivity measurements reveals a good charge carrier mobility (0.2 cm(2) V-1 s(-1)) and a relatively long lifetime (200 ns) for photogenerated charge carriers. Conversely, systematic PEC measurements with varied redox systems reveal the existence of a high density of surface states (10(14) cm(-2)) positioned 0.35 eV above the conduction band, inducing Fermi level pinning at the semiconductor-liquid junction. X-ray photoelectron spectroscopy suggests the presence of a thin layer of metal hydroxide at the surface of the material. These surface states were found to behave as electron traps, correlated with an inversion of polarity at the surface of the semiconductor, and thereby promoting charge recombination and limiting the photovoltage developed at the junction. These findings suggest that if the detrimental effects of the surface states can be eliminated, CuFeO2 would provide a sufficiently high photovoltage to be combined with other solution-processed and stable photoanodes into an easily scalable tandem PEC cell