138 research outputs found

    Water Consumption Behavior in Broilers

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    A series of trials were conducted to analyze broiler water consumption behaviors under commercial conditions. The first trial was to quantify the number of broilers drinking at times of peak water demand. Birds were evaluated at time intervals of 5, 10, 15, 30, 45, and 60 minutes from the start of the light period to establish the percentage birds having consumed water by that point in time. Significant differences were found by bird age in the 5, 10, and 15 minute intervals, however there were no significant differences in the percentage of birds having consumed water in the 30, 45, and 60 minute intervals. A second trial was conducted to evaluate the percentage of birds drinking while on pre-slaughter feed withdrawal. Birds were evaluated at four, hourly intervals after feed had been withdrawn. It was found that there was no significant difference between the percentage of birds drinking during each hour of feed withdrawal when compared to birds that had not had feed withdrawn. Additionally, water utilization rates of liters/100 birds in the first, second, and third hour of feed withdrawal were established. A third trial evaluated the daily water to feed intake ratios on a commercial broiler farm and investigated the changes in this ratio by season. It was demonstrated that water to feed intake ratios become smaller as the birds age, ranging from 1.931:1 at 11 days of age to 1.715:1 at 46 days of age. Also, it was found that significant differences exist in daily water to feed ratios by season. A fourth and final trial was conducted to evaluate the relationship between changes in lighting and changes in water intake. Daily records of lighting changes and water consumption were collected from six farms in two different integrator complexes. These records were analyzed and no statistically significant effect (P\u3e0.0554) of changing lighting intensity or duration on daily water consumption by broilers

    Solid-State Protein Junctions:Cross-Laboratory Study Shows Preservation of Mechanism at Varying Electronic Coupling

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    Successful integration of proteins in solid-state electronics requires contacting them in a non-invasive fashion, with a solid conducting surface for immobilization as one such contact. The contacts can affect and even dominate the measured electronic transport. Often substrates, substrate treatments, protein immobilization, and device geometries differ between laboratories. Thus the question arises how far results from different laboratories and platforms are comparable and how to distinguish genuine protein electronic transport properties from platform-induced ones. We report a systematic comparison of electronic transport measurements between different laboratories, using all commonly used large-area schemes to contact a set of three proteins of largely different types. Altogether we study eight different combinations of molecular junction configurations, designed so that Ageo of junctions varies from 105 to 10−3 μm2. Although for the same protein, measured with similar device geometry, results compare reasonably well, there are significant differences in current densities (an intensive variable) between different device geometries. Likely, these originate in the critical contact-protein coupling (∼contact resistance), in addition to the actual number of proteins involved, because the effective junction contact area depends on the nanometric roughness of the electrodes and at times, even the proteins may increase this roughness. On the positive side, our results show that understanding what controls the coupling can make the coupling a design knob. In terms of extensive variables, such as temperature, our comparison unanimously shows the transport to be independent of temperature for all studied configurations and proteins. Our study places coupling and lack of temperature activation as key aspects to be considered in both modeling and practice of protein electronic transport experiments

    Enhancement of the electrochemical performance of SWCNT dispersed in a Silica Sol-Gel matrix by reactive Insertion of a Conducting Polymer

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    The electroassisted encapsulation of Single-Walled Carbon Nanotubes was performed into silica matrices (SWCNT@SiO2). This material was used as the host for the potentiostatic growth of polyaniline (PANI) to yield a hybrid nanocomposite electrode, which was then characterized by both electrochemical and imaging techniques. The electrochemical properties of the SWCNT@SiO2-PANI composite material were tested against inorganic (Fe3+/Fe2+) and organic (dopamine) redox probes. It was observed that the electron transfer constants for the electrochemical reactions increased significantly when a dispersion of either SWCNT or PANI was carried out inside of the SiO2 matrix. However, the best results were obtained when polyaniline was grown through the pores of the SWCNT@SiO2 material. The enhanced reversibility of the redox reactions was ascribed to the synergy between the two electrocatalytic components (SWCNTs and PANI) of the composite material. (C) 2014 Elsevier Ltd. All rights reserved.This work was financed by the following research projects: MAT2010-15273 of the Spanish Ministerio de Economia y Competitividad and CIVP16A1821 of the Fundacion Ramon Areces and PROMETEO 2013/038 of the Generalitat Valenciana. Alonso Gamero-Quijano is grateful to Generalitat Valenciana (Santiago Grisolia Program) for the funding of his research fellowship. David Salinas-Torres is grateful to Ministerio de Economia y Competitividad for the funding of his research fellowship.Gamero-Quijano, A.; Huerta, F.; Salinas Torres, D.; Morallón, E.; Montilla, F. (2014). Enhancement of the electrochemical performance of SWCNT dispersed in a Silica Sol-Gel matrix by reactive Insertion of a Conducting Polymer. Electrochimica Acta. 135:114-120. https://doi.org/10.1016/j.electacta.2014.04.172S11412013

    Organic electrode coatings for next-generation neural interfaces

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    Traditional neuronal interfaces utilize metallic electrodes which in recent years have reached a plateau in terms of the ability to provide safe stimulation at high resolution or rather with high densities of microelectrodes with improved spatial selectivity. To achieve higher resolution it has become clear that reducing the size of electrodes is required to enable higher electrode counts from the implant device. The limitations of interfacing electrodes including low charge injection limits, mechanical mismatch and foreign body response can be addressed through the use of organic electrode coatings which typically provide a softer, more roughened surface to enable both improved charge transfer and lower mechanical mismatch with neural tissue. Coating electrodes with conductive polymers or carbon nanotubes offers a substantial increase in charge transfer area compared to conventional platinum electrodes. These organic conductors provide safe electrical stimulation of tissue while avoiding undesirable chemical reactions and cell damage. However, the mechanical properties of conductive polymers are not ideal, as they are quite brittle. Hydrogel polymers present a versatile coating option for electrodes as they can be chemically modified to provide a soft and conductive scaffold. However, the in vivo chronic inflammatory response of these conductive hydrogels remains unknown. A more recent approach proposes tissue engineering the electrode interface through the use of encapsulated neurons within hydrogel coatings. This approach may provide a method for activating tissue at the cellular scale, however, several technological challenges must be addressed to demonstrate feasibility of this innovative idea. The review focuses on the various organic coatings which have been investigated to improve neural interface electrodes

    Next Generation Nuclear Plant Methods Technical Program Plan

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    One of the great challenges of designing and licensing the Very High Temperature Reactor (VHTR) is to confirm that the intended VHTR analysis tools can be used confidently to make decisions and to assure all that the reactor systems are safe and meet the performance objectives of the Generation IV Program. The research and development (R&D) projects defined in the Next Generation Nuclear Plant (NGNP) Design Methods Development and Validation Program will ensure that the tools used to perform the required calculations and analyses can be trusted. The Methods R&D tasks are designed to ensure that the calculational envelope of the tools used to analyze the VHTR reactor systems encompasses, or is larger than, the operational and transient envelope of the VHTR itself. The Methods R&D focuses on the development of tools to assess the neutronic and thermal fluid behavior of the plant. The fuel behavior and fission product transport models are discussed in the Advanced Gas Reactor (AGR) program plan. Various stress analysis and mechanical design tools will also need to be developed and validated and will ultimately also be included in the Methods R&D Program Plan. The calculational envelope of the neutronics and thermal-fluids software tools intended to be used on the NGNP is defined by the scenarios and phenomena that these tools can calculate with confidence. The software tools can only be used confidently when the results they produce have been shown to be in reasonable agreement with first-principle results, thought-problems, and data that describe the “highly ranked” phenomena inherent in all operational conditions and important accident scenarios for the VHTR

    2D nanosheet molybdenum disulphide (MoS2) modified electrodes explored towards the hydrogen evolution reaction

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    We explore the use of two-dimensional (2D) MoS2 nanosheets as an electro-catalyst for the Hydrogen Evolution Reaction (HER). Using four commonly employed commercially available carbon based electrode support materials, namely edge plane pyrolytic graphite (EPPG), glassy carbon (GC), boron-doped diamond (BDD) and screen-printed graphite electrodes (SPE), we critically evaluate the reported electro-catalytic performance of unmodified and MoS2 modified electrodes towards the HER. Surprisingly, current literature focuses almost exclusively on the use of GC as an underling support electrode upon which HER materials are immobilised. 2D MoS2 nanosheet modified electrodes are found to exhibit a coverage dependant electrocatalytic effect towards the HER. Modification of the supporting electrode surface with an optimal mass of 2D MoS2 nanosheets results in a lowering of the HER onset potential by ca. 0.33, 0.57, 0.29 and 0.31 V at EPPG, GC, SPE and BDD electrodes compared to their unmodified counterparts respectively. The lowering of the HER onset potential is associated with each supporting electrodes individual electron transfer kinetics/properties. The effect of MoS2 coverage is also explored. We reveal that its ability to catalyse the HER is dependent on the mass deposited until a critical mass of 2D MoS2 nanosheets is achieved, after which its electrocatalytic benefits and/or surface stability curtail. The active surface site density and turn over frequency for the 2D MoS2 nanosheets is determined, characterised and found to be dependent on both the coverage of 2D MoS2 nanosheets and the underlying/supporting substrate. This work is essential for those designing, fabricating and consequently electrochemically testing 2D nanosheet materials for the HER

    Molecule-Electrode Interface Energetics in Molecular Junction: a Transition Voltage Spectroscopy Study

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    We assess the performances of the transition voltage spectroscopy (TVS) method to determine the energies of the molecular orbitals involved in the electronic transport though molecular junctions. A large number of various molecular junctions made with alkyl chains but with different chemical structure of the electrode-molecule interfaces are studied. In the case of molecular junctions with clean, unoxidized electrode-molecule interfaces, i.e. alkylthiols and alkenes directly grafted on Au and hydrogenated Si, respectively, we measure transition voltages in the range 0.9 - 1.4 V. We conclude that the TVS method allows estimating the onset of the tail of the LUMO density of states, at energy located 1.0 - 1.2 eV above the electrode Fermi energy. For oxidized interfaces (e.g. the same monolayer measured with Hg or eGaIn drops, or monolayers formed on a slightly oxidized silicon substrate), lower transition voltages (0.1 - 0.6 V) are systematically measured. These values are explained by the presence of oxide-related density of states at energies lower than the HOMO-LUMO of the molecules. As such, the TVS method is a useful technique to assess the quality of the molecule-electrode interfaces in molecular junctions.Comment: Accepted for publication in J. Phys. Chem C. One pdf file including manuscript, figures and supporting informatio

    Neutral tumor evolution in myeloma is associated with poor prognosis

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    Recent studies suggest that the evolutionary history of a cancer is important in forecasting clinical outlook. To gain insight into the clonal dynamics of multiple myeloma (MM) and its possible influence on patient outcome we analysed whole exome sequencing tumor data for 333 patients from Myeloma XI, a UK phase III trial and 434 patients from the CoMMpass study, all of which had received immunomodulatory therapy (IMiD). By analysing mutant allele frequency distributions in tumors we found that 17-20% of MM is under neutral evolutionary dynamics. These tumors are associated with poorer patient survival in non-intensively treated patients, consistent with reduced therapeutic efficacy of micro-environment modulating IMiD drugs. Our findings provide evidence that knowledge of the evolutionary history of MM has relevance for predicting patient outcome and personalising therapy
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