Effects of Instrumental Insemination and Insemination Quantity on Dufour’s Gland Chemical Profiles and <Emphasis Type="Italic">Vitellogenin</Emphasis> Expression in Honey Bee Queens (<Emphasis Type="Italic">Apis mellifera</Emphasis>)

Honey bee queens (Apis mellifera) mate in their early adult lives with a variable number of males (drones). Mating stimulates dramatic changes in queen behavior, physiology, gene expression, and pheromone production. Here, we used virgin, single drone- (SDI), and multi-drone- (MDI) inseminated queens to study the effects of instrumental insemination and insemination quantity on the pheromone profiles of the Dufour’s gland, and the expression of the egg-yolk protein, vitellogenin, in the fat body. Age, environmental conditions, and genetic background of the queens were standardized to specifically characterize the effects of these treatments. Our data demonstrate that insemination and insemination quantity significantly affect the chemical profiles of the Dufour’s gland secretion. Moreover, workers were more attracted to Dufour’s gland extract from inseminated queens compared to virgins, and to the extract of MDI queens compared to extract of SDI queens. However, while there were differences in the amounts of some esters between MDI queens and the other groups, it appears that the differences in behavioral responses were elicited by subtle changes in the overall chemical profiles rather than dramatic changes in specific individual chemicals. We also found a decrease in vitellogenin gene expression in the fat body of the MDI queens, which is negatively correlated with the quantities of Dufour’s gland content. The possible explanations of this reduction are discussed.     

A calibrated direct conversion front-end transmitter with resonant matching techniques for mobile WiMAX/WiBro applications

A direct conversion front-end transmitter with the properties of high linearity and high single sideband rejection ratio is described in this paper. The transmitter employs two resonant matching techniques to improve its operating bandwidth. The first resonant circuit design is applied at the inter-stage of the LO input buffer in order to achieve a wideband frequency response which ranges from dc to 6 GHz. The second resonant circuit is applied at the power amplifier (PA) driver output stage to increase the matching bandwidth and meet both the Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Broadband (WiBro) applications simultaneously. In addition, the sideband signal and carrier leakage of this transmitter are further minimized by a proposed calibration circuit design to achieve the error vector magnitude (EVM) specifications. The measured single sideband performance with calibration mechanism demonstrates approximately 15 dB improvement on sideband and carrier suppression. The rejected sideband and carrier signals can be up to 55.19 and 56.31 dBc, respectively. The measured dynamic gain range of the transmitter is 53 dB in 1-dB step with a maximum relative gain error lower than 0.4 dB. The transmitter delivers +0.766 dBm output power with EVM of −34.687 dB for the orthogonal frequency division multiple access (OFDMA) 64QAM-3/4 modulated signals. The measured constellation is minimized to be <1.5% with output power from −2.3 to −36.2 dBm.     

Low molecular weight components in an aquatic humic substance as characterized by membrane dialysis and orbitrap mass spectrometry

Suwannee River fulvic acid (SRFA) was dialyzed through a 100-500 molecular weight cutoff dialysis membrane, and the dialysate and retentate were analyzed by UV-visible absorption and high-resolution Orbitrap mass spectrometry (MS). A significant fraction (36% based on dissolved organic carbon) of SRFA passed through the dialysis membrane. The fraction of SRFA in the dialysate had a different UV-visible absorption spectrum and was enriched in low molecular weight molecules with a more aliphatic composition relative to the initial SRFA solution. Comparison of the SRFA spectra collected by Orbitrap MS and Fourier transform ion cyclotron resonance MS (FT-ICR MS) demonstrated that the mass accuracy of the Orbitrap MS is sufficient for determination of unique molecular formulas of compounds with masses <600 Da in a complex mixture, such as SRFA. The most intense masses detected by Orbitrap MS were found in the 100-200 Da mass range. Many of these low molecular masses corresponded to molecular formulas of previously identified compounds in organic matter, lignin, and plants, and the use of the standard addition method provided an upper concentration estimate of selected target compounds in SRFA. Collectively, these results provide evidence that SRFA contains low molecular weight components that are present individually or in loosely bound assemblies.     

Stable anatase TiO₂ coating on quartz fibers by atomic layer deposition for photoactive light-scattering in dye-sensitized solar cells

Quartz fibers provide a unique high surface-area substrate suitable for conformal coating using atomic layer deposition (ALD), and are compatible with high temperature annealing. This paper shows that the quartz fiber composition stabilizes ALD TiO(2) in the anatase phase through TiO(2)-SiO(2) interface formation, even after annealing at 1050 °C. When integrated into a dye-sensitized solar cell, the TiO(2)-coated quartz fiber mat improves light scattering performance. Results also confirm that annealing at high temperature is necessary for better photoactivity of ALD TiO(2), which highlights the significance of quartz fibers as a substrate. The ALD TiO(2) coating on quartz fibers also boosts dye adsorption and photocurrent response, pushing the overall efficiency of the dye-cells from 6.5 to 7.4%. The mechanisms for improved cell performance are confirmed using wavelength-dependent incident photon to current efficiency and diffuse light scattering results. The combination of ALD and thermal processing on quartz fibers may enable other device structures for energy conversion and catalytic reaction applications.     

Determination of free fatty acids in edible oils by 1H NMR spectroscopy

Here we describe a novel ¹H NMR assay for the determination of FFAs in edible oils. The analytical performance of the NMR assay is similar to that of the commonly used acid value (AV) method. A total of 120 edible oil samples were analysed by both approaches. Except for pumpkin seed oil, showing slight deviations, there was a good compliance between the results obtained from the two methods.     

Evaluation of packet scheduling in hybrid optical/electrical switch

This paper presents a hybrid optical/electrical switch for high-capacity future network development. A switch architecture to provide packet switching by solving contention in wavelength and time domains is considered relying on available optical and electrical technology. Physical and logical aspects regarding switch feasibility and management, in relation to the hybrid nature of the switch, are addressed. Scheduling algorithms to support multi-service packet forwarding are compared with optimally exploit optical and electrical subsystems according to traffic characteristics and needs. The main outcomes of the paper suggest criteria to design high-capacity packet switches, based on present-day technology constraints and quality of service requirements, to achieve a fair balance between optical transparency and loss performance.     

为聚酯短纤维生产打造一个全新的标准

为了抓住日趋增长的聚酯短纤维市场,短纤厂家需要一个长期的竞争战略。一条来自Oerlikon Neumag(欧瑞康纽马格)的高产能,日产300t的短纤维生产线将降低用户的运营成本。拥有50年短纤制造经验和超过25条日产200t设备实践经验的欧瑞康纽马格是值得信赖的合作伙伴。     

Sensory evaluation and inhibition of Listeria monocytogenes in bovine pâté added of chitosan from Mucor rouxii

This study aimed to assess the efficacy of chitosan from Mucor rouxii UCP 064 in inhibiting Listeria monocytogenes in bovine meat pâté at 4 °C. The influence of the chitosan addition on sensory aspects of the product was also evaluated. The addition of chitosan from M. rouxii at 5 mg/g to bovine meat pâté decreased the counts of L. monocytogenes from approximately 7 to 3 log cfu/g after 6 days of storage at 4 °C. In pâté without chitosan the counts were over 7 log cfu/g already after two days of storage. Sensory evaluation suggested that addition of chitosan in pâté would be acceptable to consumers, although some negative influence on flavor and taste was found. From these results, chitosan from fungi could be considered a possible alternative compound to control L. monocytogenes in ready-to-eat meat products.     

Driver distraction in an unusual environment: Effects of text-messaging in tunnels

Text messaging while driving can be distracting and significantly increases the risk of being involved in a collision. Compared to freeway driving, driving in a tunnel environment introduces factors that may interact with driver attentional resources to exacerbate the effects of distraction on driving safety. With planning and design of the 18 km Stockholm Bypass tunnel ongoing, and because of the potentially devastating consequences of crashes in long tunnels, it is critical to assess the effects of driver distraction in a tunnel environment.