SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Configuration management

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The constitution of the aglycon of nudicaulin has been revised to be a pentacyclic indole alkaloid. The relative and absolute configurations of the two diastereomers, nudicaulins I (3a) and II (3b), have been assigned by NMR, conformational analyses, and interpretation of the experimental ECD spectra by quantum-chemical calculations.

Concepts: Papaver, Configuration management, Constitution, Papaver nudicaule

27

Acapella® 27 produces high frequency oscillations and positive expiratory pressure (HFOPEP) for use in bronchial hygiene. However, its performance in aerosol delivery has not been described. The aim of this study was to evaluate the effect of nebulizer configuration in relation to the HFOPEP device on deposition of radiotagged aerosols with healthy subjects.

Concepts: Asthma, Aerosol, Dosage forms, Nebulizer, Aerosol spray, Configuration management, CS gas

22

Motivated by the lack of research in tailless morphing aircraft in addition to the current inability to measure the resultant aerodynamic forces and moments of bird control maneuvers, this work aims to develop and test a multi-functional morphing control surface based on the horizontal tail of birds for a low-radar-signature UAV. Customized Macro Fiber Composite (MFC) actuators were designed to achieve yaw control across a range of sideslip angles by inducing three dimensional curvature as a result of bending-twisting coupling, a well-known phenomenon in classical fiber composite theory. This allows for yaw control, pitch control, and limited air break control. The structural response of the customized actuators was determined numerically using both a piezoelectric and an equivalent thermal model in order to optimize the fiber direction to allow for maximized deflection in both the vertical and lateral directions. In total, three control configurations were tested experimentally: symmetric deflection for pitch control, single-sided deflection for yaw control, and antisymmetric deflection for air brake control. A Reynolds-averaged-Navier-Stokes (RANS) fluid simulation was also developed to compare with the experimental results for the unactuated baseline configuration. The actuator was shown to provide better yaw control than traditional split aileron methods, remain effective in larger sideslip angles, and provide directional yaw stability when unactuated. Furthermore, it was shown to provide adequate pitch control in sideslip in addition to limited air brake capabilities. This design is proposed to provide complete aircraft control in concert with spanwise morphing wings.

Concepts: Aerodynamics, Fixed-wing aircraft, Configuration management, Aviation terminology, Aerospace engineering, Sideslip angle, Empennage

14

Selective configuration control of plasmonic nanostructures using either top-down or bottom-up approaches has remained challenging in the field of active plasmonics. We demonstrate the realization of DNA-assembled reconfigurable plasmonic metamolecules, which can respond to a wide range of pH changes in a programmable manner. This programmability allows for selective reconfiguration of different plasmonic metamolecule species coexisting in solution through simple pH tuning. This approach enables discrimination of chiral plasmonic quasi-enantiomers and arbitrary tuning of chiroptical effects with unprecedented degrees of freedom. Our work outlines a new blueprint for implementation of advanced active plasmonic systems, in which individual structural species can be programmed to perform multiple tasks and functions in response to independent external stimuli.

Concepts: Degree, PH, Computer program, Plasmon, Program, Configuration management

2

Groundwater contamination by petroleum hydrocarbons (PHs) is a widespread problem which poses serious environmental and health concerns. Recently, microbial electrochemical technologies (MET) have attracted considerable attention for remediation applications, having the potential to overcome some of the limiting factors of conventional in situ bioremediation systems. So far, field-scale application of MET has been largely hindered by the limited availability of scalable system configurations. Here, we describe the ‘bioelectric well’ a bioelectrochemical reactor configuration, which can be installed directly within groundwater wells and can be applied for in situ treatment of organic contaminants, such as PHs. A laboratory-scale prototype of the bioelectric well has been set up and operated in continuous-flow regime with phenol as the model contaminant. The best performance was obtained when the system was inoculated with refinery sludge and the anode potentiostatically controlled at +0.2 V versus SHE. Under this condition, the influent phenol (25 mg l(-1) ) was nearly completely (99.5 ± 0.4%) removed, with an average degradation rate of 59 ± 3 mg l(-1) d and a coulombic efficiency of 104 ± 4%. Microbial community analysis revealed a remarkable enrichment of Geobacter species on the surface of the graphite anode, clearly pointing to a direct involvement of this electro-active bacterium in the current-generating and phenol-oxidizing process.

Concepts: Bacteria, Microbiology, Water, Electrochemistry, Petroleum, Soil contamination, Water well, Configuration management

0

Three experiments were conducted to evaluate the effects of roller mill configuration on growth performance of nursery and finishing pigs, feed preference, and feed mill throughput. The 4 experimental treatments included corn ground through a roller mill using 2, 3, 4 sets of rolls in a fine grind configuration, or 4 sets of rolls in a coarse grind configuration. The same roller mill was used for all configurations with the appropriate lower rolls completely open when using the 2 or 3 roll pair configurations. Across all studies, mean particle size averaged approximately 540, 435, 270, and 385 µm for the 4 roller mill configurations, respectively. In Exp. 1, 320 pigs (DNA 400 × 200, initially 10.7 ± 0.27 kg BW) were randomly allotted to treatments with 5 pigs per pen and 16 pens per treatment in a 21-d growth trial. While there were no evidence of differences observed for ADG or ADFI, pigs fed corn ground using the 4-high coarse configuration had a marginally significant (P = 0.091) improvement in G:F compared to those fed with the 2-high configuration, with others intermediate. In Exp. 2, 90 pigs (PIC 327 × 1050, initially 12.1 ± 0.25 kg BW) were randomly allotted to 1 of 3 diet comparisons to determine feed preference between the 2-high, 4-high fine, and 4-high coarse configurations. When given a choice, pigs consumed more (P < 0.05) of the diet containing corn ground through the 2-high roller mill (67%) or 4-high coarse configuration (63%) compared to corn ground through the 4-high fine configuration. In Exp. 3, 922 finishing pigs (PIC TR4 × [FAST Large white × PIC Line 2], initially 40.1 ± 0.36 kg BW) were used in a 97-d experiment with pens of pigs randomly allotted by initial BW to the same experimental treatments used in Exp. 1. There were 21 pigs per pen and 11 pens per treatment. Pigs fed corn ground with the 2-high configuration had greater (P < 0.05) ADG compared to those fed corn ground using the 3-high configuration. Pigs fed corn ground with the 4-high fine configuration had the poorest (P < 0.05) ADG. No differences were observed in G:F. Grinding rate (tonne/h) was greatest (P < 0.05) for the 4-high coarse configuration, while net electricity consumption (kWh/tonne) was lowest (P < 0.05) for the 2-high configuration and greatest for the 4-high fine configuration. In summary, nursery pig G:F tended to be greatest using the 4-high coarse configuration, and finishing pig ADG was maximized using the 2 and 4-high coarse configurations.

Concepts: Experiment, Maize, Pig, Diet of Japan, Pen, Configuration management

0

Little is known about how practices reorganize when transitioning from traditional practice organization to team-based care. We compared practice-level (1) configuration as well as practice- and team-level (2) size and (3) composition, before and after establishing teams. We employed a pre-/poststudy using personnel lists of 1571 to 1711 staff (eg, job licenses, titles, and team assignment) and practice manager surveys. All personnel (physician and nonphysician) worked within 18 Massachusetts academic primary care practices participating in a 2-year learning collaborative aimed at establishing team-based care. We found that establishing team-based care can involve changing practice configurations and composition without substantially changing practice size.

Concepts: Change, General practitioner, Best practice, Team, Labour economics, Job interview, Job, Configuration management

0

Synthesis techniques such as chemical vapor deposition yield graphene in polycrystalline flakes where single-crystal domains are separated by grain boundaries (GBs) of irregular shape. These structural defects are mostly made up of pentagon-heptagon pairs and represent an important source of scattering, thus strongly affecting electronic mobilities in polycrystalline graphene (PG). In the present article, first-principles simulations are performed to explore charge transport through a GB in PG using the Landauer-Büttiker formalism implemented within the Green’s function approach. In ideal GB configurations, electronic transport is found to depend on their topology as already suggested in the literature. However, more realistic GBs constructed out of various carbon rings and with more complex periodicities are also considered, possibly inducing leakage currents. Finally, additional realistic disorder such as vacancies, a larger inter-connectivity region and out-of plane buckling is investigated. For specific energies, charge redistribution effects related to the detailed GB topology are found to substantially alter the transmissions. Altogether, the transport gap is predicted to be inversely proportional to the smallest significant periodic pattern and nearly independent of the interface configuration.

Concepts: Present, Fundamental physics concepts, Petroleum, Chemistry, Ab initio, Chemical vapor deposition, Silicon carbide, Configuration management

0

Amphidinol 3 (AM3) is a marine natural product produced by the dinoflagellate Amphidinium klebsii. Although the absolute configuration of AM3 was determined in 1999 by extensive NMR analysis and degradation of the natural product, it was a daunting task due to the presence of numerous stereogenic centers on the acyclic carbon chain and the limited availability from natural sources. Thereafter, revisions of the absolute configurations at C2 and C51 were reported in 2008 and 2013, respectively. Herein, we revised the absolute configuration of AM3 to be 32S, 33R, 34S, 35S, 36S, and 38S based on the chemical synthesis of partial structures corresponding to the C31-C67 section of AM3 in combination with degradation of the natural product. The revised structure is unique in that both antipodal tetrahydropyran counterparts exist on a single carbon chain. The structural revision of AM3 may affect proposed structures of congeners related to the amphidinols.

Concepts: Chemical reaction, Structure, Stereochemistry, Chemical element, Revision, Revise, Configuration management, Limited Brands

0

To perform a comparative analysis of the palatal bone thickness in Thai patients exhibiting class I malocclusion according to whether they exhibited a normal or open vertical skeletal configuration using cone-beam computed tomography (CBCT).

Concepts: Class I railroad, Configuration management