New composite films based on MoO<Subscript>3−<Emphasis Type="Italic">x</Emphasis></Subscript> nanowires aligned in a liquid single crystal elastomer matrix

Abstract  

In this study, we report the preparation, structure characterization, and application of new MoO_3−x nanowires, promising candidates for lithium intercalation, hydrogen sensing, and smart windows due to their photochromic property. These nanowires are a mixture of MoO₃ and conductive Mo₅O₁₄ phase and have been used to prepare composite films based on liquid single crystal elastomers (LSCE). The structure, morphology, and thermomechanic behavior of these films are discussed. In particular, we show that the particular combination of molybdenum-based nanowires and LSCEs allows for doping of liquid single crystal elastomers, preserving the pristine mechanical and optical properties of the host matrix.     

Effects of total iron, myoglobin, hemoglobin, and lipid oxidation of uncooked muscles on livery flavor development and volatiles of cooked beef steaks

Infraspinatus (IN), gluteus medius (GM), and psoas major (PM) steaks were obtained from A- and B-maturity carcasses with either high (6.0) or normal (5.7) pH, and either Slight or Small marbling. Steaks were vacuum aged either 7, 14, 21, or 35 d postmortem, and were broiled and served to a highly trained, flavor-profile sensory panel. Steaks with livery flavor were analyzed by gas chromatography/mass spectrometry for flavor compounds. Steaks aged 7 or 35 d postmortem were analyzed for myoglobin (Mb) and hemoglobin (Hb) concentrations and for total iron (Fe) (35 d steaks only). The IN had greater Fe (P < 0.05) than did the GM or PM. Livery flavor increased (P < 0.05) and beef flavor identification decreased (P < 0.05) in the GM as Fe increased. The PM had the lowest (P < 0.05) Mb/Fe ratios and highest (P < 0.05) Hb/Fe ratios. Several statistically significant, but relatively low correlations between 16-, 17-, and 18-carbon chain fatty acids and livery flavor resulted. Thirteen volatile compounds had higher concentrations in steaks with livery flavor than in those without livery flavor. Livery flavor development is a complex trait that can be affected by concentrations of total Fe, Mb, and fatty acids, but the relationships are relatively low.     

Detection of External and Internal Insect Infestation in Wheat by Near-Infrared Reflectance Spectroscopy

Near-infrared spectroscopy (NIR) in the reflectance mode was investigated for the rapid, automatic and non-destructive detection of insect stored-grain pests external or internal to wheat kernels. Convincing calibration performance was obtained for external adult Oryzaephilus surinamensis (L) (saw-toothed grain beetle) in unmilled samples including varieties Beaver (soft wheat) and Mercia (hard wheat) at two moisture contents. With this large substrate variability, the method could differentiate between uninfested samples and samples with approximately 270 insects kg⁻¹ or more. Milling made no improvement. Large spectral differences were observed between uninfested kernels and kernels infested internally with Sitophilus granarius (L) (grain weevil) larvae or pupae, arising from both a changed chemical composition and physical structure. Single uninfested and infested kernels were discriminated by their second derivative (d²) spectra. For both external and internal infestation there was substantial evidence that insect protein and/or chitin and moisture were being detected. NIR should be useful as a rapid method of detection.