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71.
Oil migration in filled pralines is a phenomenon that is highly correlated with the occurrence of chocolate bloom. In this study the potential to suppress or prevent oil migration by incorporation of sterol/sterolster-structured organogels was evaluated. Different quantities, 2.5 or 14% (w/w), of gel with structurant levels of either 10 or 25% (w/w) were studied in a layered model system. The gel was either a part of the nougat or of the chocolate phase, or as a separate layer. Samples were monitored regularly for a period of 24 weeks at storage temperatures of 10, 18 and 28 °C. The amount of migrated oil was determined via DSC analysis of a surface sample. The results indicate that, despite the additional oil brought into the system via the oleogel, the level of oil found in the chocolate layer is reduced through the presence of the gel. In particular, the three-layer system and gelled chocolate appear to be promising routes to either suppress oil migration or improve nutritional profiles by incorporation of liquid oils.  相似文献   
72.
Reproduction in social insect societies reflects a delicate balance between cooperation and conflict over offspring production, and worker reproduction is widespread even in species showing strong reproductive skew in favor of the queen. To navigate these conflicts, workers are predicted to develop the means to estimate the queen’s fecundity - potentially through behavioral and/or chemical cues - and to adjust their reproduction to maximize their fitness. Here, we introduced bumble bee, Bombus impatiens, workers to queens of different mating and reproductive status and examined worker reproduction and expression levels of two genes which were previously shown to be sensitive to the presence of the queen, vitellogenin and Krüppel-homolog 1. We further explored whether the queen’s chemical secretion alone is sufficient to regulate worker reproduction, aggression and gene expression. We found that worker ovary activation was inhibited only in the presence of egg-laying queens, regardless of their mating status. Workers reared in the presence of newly-mated queens showed intermediate vitellogenin expression levels relative to workers reared with mated egg-laying and virgin queens. However, none of the whole-body chemical extracts of any of the queen treatment groups affected ovary activation, aggressive behavior, or gene expression in workers. Our findings indicate that only the presence of a freely-behaving, egg-laying queen can fully inhibit worker reproduction. It remains to be determined if workers detect differences in queen mating status and fecundity through differences in the queens’ behavior alone or through the queen’s behavior in concert with fertility signals.  相似文献   
73.
Queens and workers are not morphologically differentiated in the primitively eusocial wasp, Ropalidia marginata. Upon removal of the queen, one of the workers becomes extremely aggressive, but immediately drops her aggression if the queen is returned. If the queen is not returned, this hyper-aggressive individual, the potential queen (PQ), will develop her ovaries, lose her hyper-aggression, and become the next colony queen. Because of the non-aggressive nature of the queen, and because the PQ loses her aggression by the time she starts laying eggs, we hypothesized that regulation of worker reproduction in R. marginata is mediated by pheromones rather than by physical aggression. Based on the immediate loss of aggression by the PQ upon return of the queen, we developed a bioassay to test whether the queen’s Dufour’s gland is, at least, one of the sources of the queen pheromone. Macerates of the queen’s Dufour’s gland, but not that of the worker’s Dufour’s gland, mimic the queen in making the PQ decrease her aggression. We also correctly distinguished queens and workers of R. marginata nests by a discriminant function analysis based on the chemical composition of their respective Dufour’s glands.  相似文献   
74.
Reducing cost and increasing energy density are two barriers for widespread application of lithium-ion batteries in electric vehicles. Although the cost of electric vehicle batteries has been reduced by ~70% from 2008 to 2015, the current battery pack cost ($268/kWh in 2015) is still >2 times what the USABC targets ($125/kWh). Even though many advancements in cell chemistry have been realized since the lithium-ion battery was first commercialized in 1991, few major breakthroughs have occurred in the past decade. Therefore, future cost reduction will rely on cell manufacturing and broader market acceptance. This article discusses three major aspects for cost reduction: (1) quality control to minimize scrap rate in cell manufacturing; (2) novel electrode processing and engineering to reduce processing cost and increase energy density and throughputs; and (3) material development and optimization for lithium-ion batteries with high-energy density. Insights on increasing energy and power densities of lithium-ion batteries are also addressed.  相似文献   
75.
In this work, poly(ethylene oxide) (PEO)/organoclay nanocomposites with three different types of nanoclays (Cloisite 30B, Somasif JAD400, and Somasif JAD230) were prepared by melt mixing with a laboratory kneader followed by compression molding. The nanocomposites were characterized by atomic force microscopy and scanning electron microscopy. Their crystallization behavior on a hot stage was investigated with polarized optical microscopy. The size and regularity of the spherulites of the PEO matrix were altered significantly by the incorporation of Cloisite 30B, but there was not as much variation with the other two clays. The dynamic viscoelastic behavior of the PEO/organoclay nanocomposites was assessed with a strain‐controlled parallel‐plate rheometer. The effects of clay modification on the thermomechanical and rheological properties were addressed. The reinforcing effect of the organoclay was determined with dynamic mechanical analysis and tensile testing. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   
76.
In this study, the properties of polypropylene (PP) homocomposites, prepared by film‐stacking followed by hot pressing, were investigated. Alpha‐ and beta‐PP served as matrices, whereas highly oriented PP tapes of the alpha form acted as reinforcement in the homocomposites. Tapes with different draw ratios (DR = 6–12) have been produced and characterized by mechanical and wide‐angle X‐ray scattering measurements. Tapes with a DR = 8 were incorporated in a cross‐ply (CP) manner in the corresponding homocomposite laminates. Specimens were subjected to static (tensile, flexural) and dynamic (instrumented falling weight impact, IFWI) tests. The thermal and thermomechanical properties of the PP tapes and homocomposites were studied by differential scanning calorimetry and dynamic mechanical thermal analysis. The homocomposite morphology was probed by polarized light microscopy, which gave evidence of transcrystalline layer at the interface between tape and matrix. The storage modulus of the CP homocomposites was improved prominently by the tape reinforcement. In static tensile tests, the homocomposites exhibited much higher stiffness and strength when compared with the neat PP specimens. However, this was accompanied with a marked reduction in the ultimate elongation. The IFWI tests showed that both alpha‐ and the beta‐PP failed in macroscopically brittle manner, whereas the corresponding homocomposites failed in semiductile way. The homocomposite laminates prepared with beta‐PP matrix exhibited higher resistance to penetration than those with alpha‐PP. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   
77.
The inhibition of mild steel corrosion in aerated 0.5 N H2SO4 solution was investigated using potentiodynamic polarization studies (Tafel), linear polarization studies, electrochemical impedance spectroscopy studies, adsorption studies, and surface morphological studies. The effect of inhibitor concentration on corrosion rate, the effect of temperature, degree of surface coverage, adsorption kinetics, and surface morphology are investigated. The inhibition efficiency increased markedly with increase in the additive concentration and decreased slightly with increasing temperature. The presence of DMSTT decrease the double-layer capacitance and increase the charge transfer resistance. The value of activation energy (E a) of metal corrosion, adsorption equilibrium constant (K ads), and free energy of adsorption (ΔG ads) were calculated from the temperature dependence of corrosion current. The adsorption of inhibitor molecule on mild steel surface follow Langmuir isotherm. DMSTT offers excellent inhibition properties and acts as a mixed-type inhibitor.  相似文献   
78.
Follicle-stimulating hormone (FSH) and luteinising hormone (LH) play important roles in regulating cell growth and proliferation in the ovary. However, few studies have explored the expression of FSH and LH receptors (FSHR and LHCGR) in ovarian cancer, and their functional roles in cancer progression remain inconclusive. This study investigated the potential impact of both mRNA (FSHR, LHCGR) and protein (FSHR, LHCGR) expression on ovarian cancer progression using publicly available online databases, qRT-PCR (high grade serous ovarian cancers, HGSOC, n = 29 and benign ovarian tumors, n = 17) and immunohistochemistry (HGSOC, n = 144). In addition, we investigated the effect of FSHR and LHCGR siRNA knockdown on the pro-metastatic behavior of serous ovarian cancer cells in vitro. High FSHR or high LHCGR expression in patients with all subtypes of high-grade ovarian cancer was significantly associated with longer progression-free survival (PFS) and overall survival (OS). High FSHR protein expression was associated with increased PFS (p = 0.050) and OS (p = 0.025). HGSOC patients with both high FSHR and high LHCGR protein levels had the best survival outcome, whilst both low FSHR and low LHCGR expression was associated with poorest survival (p = 0.019). Knockdown of FSHR significantly increased the invasion of serous ovarian cancer cells (OVCAR3 and COV362) in vitro. LHCGR knockdown also promoted invasion of COV362 cells. This study highlights that lower FSHR and LHCGR expression is associated with a more aggressive epithelial ovarian cancer phenotype and promotes pro-metastatic behaviour.  相似文献   
79.
80.
The authors regret that there was an error in our publication.Considering Lingchuang Bai made great contributions to this work,Xinghong Duo and Lingchuang Bai should be co-first authors,but there was no statement that“Xinghong Duo and Lingchuang Bai contributed equally to this work”.The authors would like to apologize for any inconvenience caused.  相似文献   
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