Stable isotope ratio measurements of royal jelly samples for controlling production procedures: impact of sugar feeding

The carbon and nitrogen stable ratios of royal jelly (RJ) samples from various origins are determined using an elemental analyser linked online to an isotope ratio mass spectrometer to evaluate authenticity and adulteration. The (13)C/(12)C and (15)N/(14)N stable isotope ratios are measured in more than 500 RJs (domestic, imported and derived from feeding experiments) in order to obtain isotopic measurements that take into account seasonal, botanical and geographical effects. Authenticity intervals are established for traditional beekeeping practices, without feeding, in the range -22.48 to -27.90‰ for δ(13)C. For these samples, the δ(15)N values range from -1.58 to 7.98‰, depending on the plant sources of pollen and nectar. The δ(13)C values of the commercial samples vary from -18.54 to -26.58‰. High δ(13)C values are typical of sugar cane or corn syrups which have distinctive isotopic (13)C signatures because both plants use the C4 photosynthetic cycle, in contrast to most RJs which are derived from C3 plants. These differences in the (13)C-isotopic composition allow the detection of the addition of such sugars. RJs from traditional sources and from industrial production by sugar feeding are thus successfully distinguished.     

Speech identification based on temporal fine structure cues

The contribution of temporal fine structure (TFS) cues to consonant identification was assessed in normal-hearing listeners with two speech-processing schemes designed to remove temporal envelope (E) cues. Stimuli were processed vowel-consonant-vowel speech tokens. Derived from the analytic signal, carrier signals were extracted from the output of a bank of analysis filters. The "PM" and "FM" processing schemes estimated a phase- and frequency-modulation function, respectively, of each carrier signal and applied them to a sinusoidal carrier at the analysis-filter center frequency. In the FM scheme, processed signals were further restricted to the analysis-filter bandwidth. A third scheme retaining only E cues from each band was used for comparison. Stimuli processed with the PM and FM schemes were found to be highly intelligible (50-80% correct identification) over a variety of experimental conditions designed to affect the putative reconstruction of E cues subsequent to peripheral auditory filtering. Analysis of confusions between consonants showed that the contribution of TFS cues was greater for place than manner of articulation, whereas the converse was observed for E cues. Taken together, these results indicate that TFS cues convey important phonetic information that is not solely a consequence of E reconstruction.     

Optimisation with genetic algorithm of the acoustic performance of T-shaped noise barriers with a reactive top surface

In this study, the aim is to optimise the acoustical efficiency of T-shaped noise barriers whose top is covered with a series of wells. This research work uses an optimisation method in order to find the best noise barrier profile considering several variable parameters. Numerical simulations of the acoustical propagation are achieved by use of a 2D boundary element method code. The optimisation part is carried out with a global and direct evolutionary optimisation method: a genetic algorithm. The parameters to optimise are the shape of the protection (the depths of the wells on the crowning) and the flow resistivity of absorbing materials considered. The cost function to maximize is defined through a mean value of the acoustical efficiency of the protection compared to a reference configuration, averaged on several receiver points. Final results show significant optimised values of parameters for efficient protections in order to improve classical noise barriers.     

Laser-assisted local patterning of ZnO-based spots for mirror-less lasing

ZnO is known as one of the best materials for the implementation of the random lasing effect, associated with mirror-less laser emission in a simultaneously amplifying and highly scattering medium. Normally, the fabrication of this medium requires a rather complicated procedure of deposition and thermal treatment of ZnO-based films on some specific substrates, yielding wurtzite-orientation ZnO nanocrystals. We demonstrate a rapid synthesis of highly efficient ZnO-based random lasing spots on a piece of Zn by employing the phenomenon of laser-induced air breakdown. Being ignited near the surface of a Zn target, plasma of the air breakdown serves as a local reactor to locally transform its properties and thus form a film of well-packed 20–40 nm ZnO nanospheres. Exhibiting extremely high amplification and scattering, this medium is capable of generating the random lasing effect within the exciton-based photoluminescent band.     

Mannich-Type Reactions of Alkylzinc Reagents

Mannich-type reactions involving alkylzinc reagents have been developed using different strategies. We show that the addition of these organometallic species to sulfonyl imines occurs upon simple heating and affords Mannich products in moderate to excellent yields (14 examples, 30–99 %). Interestingly, N-alkyl imines were also found to be suitable partners after activation as an acyliminium by acetyl chloride (12 examples, 49–86 %) or, more originally, by TMSCl (14 examples, 26–87 %). These methods proved complementary, leading to the preparation of both N-protected secondary or tertiary amines and N-unprotected secondary amines in good yields, with an increased eco-compatibility, and under simple conditions.     

Hyperpolarized 13C NMR Spectroscopy of Urine Samples at Natural Abundance by Quantitative Dissolution Dynamic Nuclear Polarization

Hyperpolarized nuclear magnetic resonance (NMR) offers an ensemble of methods that remarkably address the sensitivity issues of conventional NMR. Dissolution Dynamic Nuclear Polarization (d-DNP) provides a unique and general way to detect ¹³C NMR signals with a sensitivity enhanced by several orders of magnitude. The expanding application scope of d-DNP now encompasses the analysis of complex mixtures at natural ¹³C abundance. However, the application of d-DNP in this area has been limited to metabolite extracts. Here, we report the first d-DNP-enhanced ¹³C NMR analysis of a biofluid -urine- at natural abundance, offering unprecedented resolution and sensitivity for this challenging type of sample. We also show that accurate quantitative information on multiple targeted metabolites can be retrieved through a standard addition procedure.