1,157 research outputs found

    Guided Neuronal Growth on Arrays of Biofunctionalized GaAs/InGaAs Semiconductor Microtubes

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    We demonstrate embedded growth of cortical mouse neurons in dense arrays of semiconductor microtubes. The microtubes, fabricated from a strained GaAs/InGaAs heterostructure, guide axon growth through them and enable electrical and optical probing of propagating action potentials. The coaxial nature of the microtubes -- similar to myelin -- is expected to enhance the signal transduction along the axon. We present a technique of suppressing arsenic toxicity and prove the success of this technique by overgrowing neuronal mouse cells.Comment: 3 pages, 4 figure

    Nuclear Bar Catalyzed Star Formation: 13^CO, C18^O and Molecular Gas Properties in the Nucleus of Maffei 2

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    (Abridged) We present resolution maps of CO, its isotopologues, and HCN from in the center of Maffei 2. The J=1-0 rotational lines of 12^CO, 13^CO, C18^O and HCN, and the J=2-1 lines of 13^CO and C18^O were observed with the OVRO and BIMA arrays. The 2-1/1-0 line ratios of the isotopologues constrain the bulk of the molecular gas to originate in low excitation, subthermal gas. From LVG modeling, we infer that the central GMCs have n(H_2) ~10^2.75 cm^-3 and T_k ~ 30 K. Continuum emission at 3.4 mm, 2.7 mm and 1.4 mm was mapped to determine the distribution and amount of HII regions and dust. Column densities derived from C18^O and 1.4 mm dust continuum fluxes indicate the CO conversion factor in the center of Maffei 2 is lower than Galactic by factors of ~2-4. Gas morphology and the clear ``parallelogram'' in the Position-Velocity diagram shows that molecular gas orbits within the potential of a nuclear (~220 pc) bar. The nuclear bar is distinct from the bar that governs the large scale morphology of Maffei 2. Giant molecular clouds in the nucleus are nonspherical and have large linewidths. Dense gas and star formation are concentrated at the sites of the x_1-x_2 orbit intersections of the nuclear bar, suggesting that the starburst is dynamically triggered.Comment: 50 pages, 14 figures, accepted for publication in Ap

    Defect configurations and dynamical behavior in a Gay-Berne nematic emulsion

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    To model a nematic emulsion consisting of a surfactant-coated water droplet dispersed in a nematic host, we performed a molecular dynamics simulation of a droplet immersed in a system of 2048 Gay-Berne ellipsoids in a nematic phase. Strong radial anchoring at the surface of the droplet induced a Saturn ring defect configuration, consistent with theoretical predictions for very small droplets. A surface ring configuration was observed for lower radial anchoring strengths, and a pair of point defects was found near the poles of the droplet for tangential anchoring. We also simulated the falling ball experiment and measured the drag force anisotropy, in the presence of strong radial anchoring as well as zero anchoring strength.Comment: 17 pages, 15 figure

    Probabilistic Clustering of Time-Evolving Distance Data

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    We present a novel probabilistic clustering model for objects that are represented via pairwise distances and observed at different time points. The proposed method utilizes the information given by adjacent time points to find the underlying cluster structure and obtain a smooth cluster evolution. This approach allows the number of objects and clusters to differ at every time point, and no identification on the identities of the objects is needed. Further, the model does not require the number of clusters being specified in advance -- they are instead determined automatically using a Dirichlet process prior. We validate our model on synthetic data showing that the proposed method is more accurate than state-of-the-art clustering methods. Finally, we use our dynamic clustering model to analyze and illustrate the evolution of brain cancer patients over time

    Stability of commercial phytase sources under different environmental conditions

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    Citation: De Jong, J. A., DeRouchey, J. M., Tokach, M. D., Dritz, S. S., Goodband, R. D., Woodworth, J. C., . . . Stark, C. R. (2016). Stability of commercial phytase sources under different environmental conditions. Journal of Animal Science, 94(10), 4259-4266. doi:10.2527/jas2016-0742A 300-d study was conducted to evaluate storage stability of 4 commercially available phytase products under varied environmental conditions. Products used were: 1) Quantum Blue G (AB Vista, Plantation, FL), 2) Ronozyme Hi Phos GT (DSM Nutritional Products, Parsippany, NJ), 3) Axtra Phy TPT (Dupont, Wilmington, DE), and 4) Microtech 5000 Plus (Guangdong Vtr Bio-Tech Co., Ltd., Guangdong, China). Products were stored as pure forms, in a vitamin premix, or a vitamin trace mineral (VTM) premix. Pure products were stored at -20 degrees C, 4 degrees C, 22 degrees C, or 35 degrees C (75% humidity). Vitamin and VTM premixes were stored at 22 degrees C or 35 degrees C (75% humidity). Samples were stored in open-topped paper bags and sampled on d 30, 60, 90, 120, 210, and 300. Stability was determined as the amount of residual phytase activity (% of initial) at each sampling point. For the pure forms, all interactive and main effects of phytase product, time, and storage temperature were significant (P < 0.05). From d 30 to 300, products had similar reductions in phytase activity at the 3 highest temperatures; however, Quantum Blue G, Ronozyme HiPhos GT, and Axtra Phy TPT had reduced (P < 0.05) phytase activity as compared to Microtech 5000 at -20 degrees C. In general, as storage time increased, residual phytase activity decreased (P < 0.05) regardless of product and storage temperature. When product was stored at 4 degrees C and 22 degrees C, phytase activity was greater than that of product stored at -20 degrees C or 35 degrees C, and Microtech 5000 Plus had greater (P < 0.05) stability regardless of time and temperature as compared to the other 3 products. For vitamin and VTM premixes, a time x temperature x product interaction (P < 0.05) was observed. When stored at 22 degrees C, Axtra Phy TPT and Microtech 5000 Plus had reduced residual phytase activity (P < 0.05) when compared to the other 2 products; however, when stored at 35 degrees C Axtra Phy had even further reduced (P < 0.05) activity than the other 3 products regardless of which form the products were stored in. From d 30 to 300 Axtra Phy TPT and Microtech 5000 Plus had the lowest (P < 0.05) residual phytase activity when compared to the others regardless of storage form or temperature. Phytase products stored in VTM premix had decreased (P < 0.05) residual phytase activity when compared to pure products and vitamin premixes. In conclusion, phytase stored for longer than 90 to 120 d, at both high (35 degrees C) and low (-20 degrees C) temperatures when in pure form or as a VTM premix had reduced residual phytase activity

    A New, Bright, Short-Period, Emission Line Binary in Ophiuchus

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    The 11th magnitude star LS IV -08 3 has been classified previously as an OB star in the Luminous Stars survey, or alternatively as a hot subdwarf. It is actually a binary star. We present spectroscopy, spectroscopic orbital elements, and time series photometry, from observations made at the Kitt Peak National Observatory 2.1m, Steward Observatory 2.3m, MDM Observatory 1.3m and 2.4m, Hobby-Eberly 9.2m, and Michigan State University 0.6m telescopes. The star exhibits emission of varying strength in the cores of H and He I absorption lines. Emission is also present at 4686 Angstroms (He II) and near 4640/4650 Angstroms (N III/C III). Time-series spectroscopy collected from 2005 July to 2007 June shows coherent, periodic radial velocity variations of the H-alpha line, which we interpret as orbital motion with a period of 0.1952894(10) days. High-resolution spectra show that there are two emission components, one broad and one narrow, moving in antiphase, as might arise from an accretion disk and the irradiated face of the mass donor star. Less coherent, low-amplitude photometric variability is also present on a timescale similar to the orbital period. Diffuse interstellar bands indicate considerable reddening, which however is consistent with a distance of ~100-200 pc. The star is the likely counterpart of a weak ROSAT X-ray source, whose properties are consistent with accretion in a cataclysmic variable (CV) binary system. We classify LS IV -08 3 as a new member of the UX UMa subclass of CV stars.Comment: To be published in AJ, 16 pages, 6 figures. Uses AAS Late

    Effects of grinding corn through a 2-, 3-, or 4-high roller mill on milling characteristics, and finishing pig growth performance and carcass characteristics

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    Citation: Gebhardt, J. T., Tokach, M. D., Woodworth, J. C., DeRouchey, J. M., Goodband, R. D., Coble, K. F., . . . Dritz, S. S. (2016). Effects of grinding corn through a 2-, 3-, or 4-high roller mill on milling characteristics, and finishing pig growth performance and carcass characteristics. Journal of Animal Science, 94, 59-59. doi:10.2527/msasas2016-126Finishing pigs (n = 922, initial BW = 40.1 kg) were used in a 97-d experiment to determine the effects of grinding corn through various roller mill configurations on milling characteristics and growth performance and carcass characteristics of finishing pigs in a commercial setting. Pens were randomly allotted to 1 of 4 experimental treatments by initial BW with 11 pens/treatment and 21 pigs/pen. All diets were fed in 5 phases with the same corn-soybean meal-based diets containing 20% dried distiller’s grains with solubles. Experimental treatments included corn ground to 685 µm using 2 sets of rolls (2-high), corn ground to 577 µm using 3 sets of rolls (3-high), corn ground to 360 µm using 4 sets of rolls in a fine grind configuration (4-high fine), and corn ground to 466 µm using 4 sets of rolls in a coarse grind configuration (4-high coarse). The same roller mill was used for all configurations with the appropriate lower rolls completely open when using 2 or 3 sets of rolls. Grinding rate (tonnes/hour) was greatest (P < 0.05) for the 2-high and 4-high coarse configurations followed by the 3-high configuration and lowest for the 4-high fine configuration. Electricity cost was lowest (P < 0.05) per tonne of ground corn for the 2-high configuration and was greatest for the 4-high fine configuration. Pigs fed diets containing corn ground with the 2-high configuration had the greatest (P < 0.05) ADFI and ADG with pigs fed diets with corn ground using the 4-high fine configuration having the poorest ADFI and ADG (2.81, 2.73, 2.65, 2.73 kg for ADFI and 0.987, 0.967, 0.940, 0.971 kg for ADG for 2-high, 3-high, 4-high fine, 4-high coarse, respectively). There were no differences in G:F, caloric efficiency, or carcass characteristics among pigs fed diets ground with the different roller mill configurations. Feed cost/kg gain was lowest (P < 0.05) for the 4-high coarse configuration and revenue/pig was greatest (P < 0.05) for the 2-high and 4-high coarse configurations. Income over feed cost (IOFC) was lowest (P < 0.05) for pigs fed diets with corn ground using the 4-high fine configuration; however, there were no differences in IOFC among the other milling configurations. In our study, roller mill configuration had a significant impact on grinding electricity cost, grinding rate, as well as ADFI and ADG; however, roller mill configuration had no impact on G:F

    Effects of wheat source and particle size in meal and pelleted diets on finishing pig growth performance, carcass characteristics, and nutrient digestibility

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    Citation: De Jong, J. A., Derouchey, J. M., Tokach, M. D., Dritz, S. S., Goodband, R. D., Paulk, C. B., . . . Stark, C. R. (2016). Effects of wheat source and particle size in meal and pelleted diets on finishing pig growth performance, carcass characteristics, and nutrient digestibility. Journal of Animal Science, 94(8), 3303-3311. doi:10.2527/jas2016-0370Two experiments were conducted to test the effects of wheat source and particle size in meal and pelleted diets on finishing pig performance, carcass characteristics, and diet digestibility. In Exp. 1, pigs (PIC 327 × 1050; n = 288; initially 43.8 kg BW) were balanced by initial BW and randomly allotted to 1 of 3 treatments with 8 pigs per pen (4 barrows and 4 gilts) and 12 pens per treatment. The 3 dietary treatments were hard red winter wheat ground with a hammer mill to 728, 579, or 326 ?m, respectively. From d 0 to 40, decreasing wheat particle size decreased (linear, P < 0.033) ADFI but improved (quadratic, P < 0.014) G:F. From d 40 to 83, decreasing wheat particle size increased (quadratic, P < 0.018) ADG and improved (linear, P < 0.002) G:F. Overall from d 0 to 83, reducing wheat particle size improved (linear, P < 0.002) G:F. In Exp. 2, pigs (PIC 327 × 1050; n = 576; initially 43.4 ± 0.02 kg BW) were used to determine the effects of wheat source and particle size of pelleted diets on finishing pig growth performance and carcass characteristics. Pigs were randomly allotted to pens, and pens of pigs were balanced by initial BW and randomly allotted to 1 of 6 dietary treatments with 12 replications per treatment and 8 pigs/pen. The experimental diets used the same wheat–soybean meal formulation, with the 6 treatments using hard red winter or soft white winter wheat that were processed to 245, 465, and 693 ?m and 258, 402, and 710 ?m, respectively. All diets were pelleted. Overall, feeding hard red winter wheat increased (P < 0.05) ADG and ADFI when compared with soft white winter wheat. There was a tendency (P < 0.10) for a quadratic particle size × wheat source interaction for ADG, ADFI, and both DM and GE digestibility, as they were decreased for pigs fed 465-?m hard red winter wheat and were greatest for pigs fed 402-?m soft white winter wheat. There were no main or interactive effects of particle size or wheat source on carcass characteristics. In summary, fine grinding hard red winter wheat fed in meal form improved G:F and nutrient digestibility, whereas reducing particle size of wheat from approximately 700 to 250 ?m in pelleted diets did not influence growth or carcass traits. Finally, feeding hard red winter wheat improved ADG and ADFI compared with feeding soft white winter wheat. © 2016 American Society of Animal Science. All rights reserved

    Finding the complement of the invariant manifolds transverse to a given foliation for a 3D flow

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    A method is presented to establish regions of phase space for 3D vector fields through which pass no co-oriented invariant 2D submanifolds transverse to a given oriented 1D foliation. Refinements are given for the cases of volume-preserving or Cartan-Arnol’d Hamiltonian flows and for boundaryless submanifolds
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