Social caste determination in the honey bee is assumed to be determined by the dietary status of the young larvae and translated into physiological and epigenetic changes through nutrient-sensing pathways. We have employed Illumina/Solexa sequencing to examine the small RNA content in the bee larval food, and show that worker jelly is enriched in miRNA complexity and abundance relative to royal jelly. The miRNA levels in worker jelly were 7–215 fold higher than in royal jelly, and both jellies showed dynamic changes in miRNA content during the 4th to 6th day of larval development. Adding specific miRNAs to royal jelly elicited significant changes in queen larval mRNA expression and morphological characters of the emerging adult queen bee. We propose that miRNAs in the nurse bee secretions constitute an additional element in the regulatory control of caste determination in the honey bee.

According to the thickening principle and molecular structure of thickeners, supercritical carbon dioxide (sc-CO2) thickeners were summarized and introduced by dividing into polymers, small molecular compounds, and surfactants. The properties...

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In this study, three oligomeric cationic Gemini surfactants (Ⅲ1, Ⅲ2, and Ⅲ3) were prepared from different major raw materials, including long-chain alkyl amine (dodecyl amine, tetradecyl amine or cetyl amine), formic acid, formaldehyde, diethyl amine hydrochloride and epichlorohydrin. The synthesis conditions for one of the three surfactants, bis-[2-hydroxy-3-(N,N-dimethyl-N-dodecyl)propyl]dipropylammonium chloride (Ⅲ1), were optimised by orthogonal experiments. The optimum synthesis conditions were: molar ratio of intermediate Ⅱ to intermediate Ⅰ1 = 1.0:2.2, reaction temperature = 85 °C and reaction time = 16 h. The structures of the three prepared compounds were characterised by FTIR and 1H NMR. Their thermal properties were evaluated by thermal gravimetric analysis (TGA). The Geminisurfactants prepared exhibited better surface active properties than conventional single chain cationic surfactants. With increasing carbon chain length from C12 to C16, both CMC and surface tension γ CMC decreased, while the viscosity of the thickening solution prepared with the synthesised oligomeric cationic Gemini surfactants as the main component increased. The optimum thickening formula was: 2.0 wt% Ⅲ3 + 0.8 wt% sodium salicylate (NaSal) + 0.6 wt% KCl. The viscosity of the optimum thickening formulation was 190.4 mPa s. Gemini oligomeric cationic surfactants could be used as thickeners in the production of fracturing fluids, flooding agents and drilling fluids for oil and gas production in oil fields.

Pseudocapacitive electrodes with high rate retention and good cycling stability are highly desirable in constructing high-performance supercapacitors for their rapid charge/discharge capacity and long service life, but still a challenge...

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In this paper, a method for medical image registration based on the bounded generalized Gaussian mixture model is proposed. The bounded generalized Gaussian mixture model is used to approach the joint intensity of source medical images. The mixture model is formulated based on a maximum likelihood framework, and is solved by an expectation-maximization algorithm. The registration performance of the proposed approach on different medical images is verified through extensive computer simulations. Empirical findings confirm that the proposed approach is significantly better than other conventional ones.