17 research outputs found

    Automated Control Systems and Methods for Underground Crop Harvesters

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    Methods and devices for automated adjustment of a digging implement during harvest of underground crops are described. Utilizing the devices, a digging implement, e.g., a blade, can be located and maintained at a desired depth as a harvester travels across a field. During use, the digging implement depth controls can be varied as the harvester travels within a single field under different operating conditions, e.g., different soil friability, consistency, etc., thereby preventing crop loss and improving crop yield

    Effects of Casting Conditions and Annealing on Microstructures and Vickers Hardness of Dendritic Pd-Cu-Ga Dental Alloys

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    Three Pd-Cu-Ga alloys with as-cast dendritic microstructures and very similar compositions, two containing less than 1 wt% boron and the third boron-free, were cast with normal bench-cooling or rapid-quenching into water. Quenched specimens were also heat treated at temperatures of 1000°, 1200°, 1500° and 1800°F that span the firing cycles for dental porcelain. Similar values of Vickers hardness were observed for all three alloys, suggesting little effect from boron on yield strength. The hardness was relatively insensitive to the experimental conditions, except for heat treatment at 1500° and 1800°F where significant softening occurred with transformation of the microstructure to Pd2Ga and the palladium solid solution

    Impact mass flow sensor for monitoring peanut harvest yields

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    Yield monitoring systems for harvesting machines and methods that can provide yield monitoring of crops are described. Machines include those that pneumatically convey crop through the machine such as peanut harvesting machines. The yield monitoring system includes a force sensor that can be located in conjunction with a duct of the harvesting machine such that impact of the crop materials on an impact plate within the duct will be registered by the force sensor. This registration can be used to determine a mass flow rate for the crop, which can be correlated to yield of the crop. The systems can include additional components such as optical monitors, moisture sensors, and pressure sensors

    Strategic considerations for invasive species managers in the utilization of environmental DNA (eDNA): Steps for incorporating this powerful surveillance tool

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    Invasive species surveillance programs can utilize environmental DNA sampling and analysis to provide information on the presence of invasive species. Wider utilization of eDNA techniques for invasive species surveillance may be warranted. This paper covers topics directed towards invasive species managers and eDNA practitioners working at the intersection of eDNA techniques and invasive species surveillance. It provides background information on the utility of eDNA for invasive species management and points to various examples of its use across federal and international programs. It provides information on 1) why an invasive species manager should consider using eDNA, 2) deciding if eDNA can help with the manager’s surveillance needs, 3) important components to operational implementation, and 4) a high-level overview of the technical steps necessary for eDNA analysis. The goal of this paper is to assist invasive species managers in deciding if, when, and how to use eDNA for surveillance. If eDNA use is elected, the paper provides guidance on steps to ensure a clear understanding of the strengths and limitation of the methods and how results can be best utilized in the context of invasive species surveillance

    Mechanism for Formation of Lamellar Constituents in Grain-Refined Pd-Cu-Ga Dental Alloys

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    Grain-refined Pd-Cu-Ga dental alloys solidify with a lamellar microstructural constituent that affects a variety of clinically relevant properties. While formation of this constituent has been attributed to eutectic solidification, an alternative mechanism of discontinuous precipitation has been proposed. Using a representative grain-refined Pd-Cu-Ga dental alloy, casting procedures involving two different rates of solidification were used: (a) A standard thin-walled coping configuration for a metal-ceramic restoration was cast into a room temperature mold, followed by rapid quenching into an ice-water mixture. (b) A thin plate specimen was cast into a standard elevated-temperature mold, with the same subsequent rapid quenching procedure. Neither casting was subjected to the standard air-abrasion procedure following devesting that is used in dental laboratories. An outer surface layer, approximately one grain thick, containing only the palladium solid solution, was observed in the microstructures of the two different castings, and the eutectic constituent was present at greater depths. This observation is consistent with physical metallurgy principles for the freezing of an alloy containing a eutectic constituent, and the alternate hypothesis that the lamellar constituents might represent discontinuous precipitates has been discarded

    Heat-Treatment Behavior of High-Palladium Dental Alloys

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    Four high-palladium dental alloys were cast, quenched following solidification, and heat treated at temperatures ranging from 200° to 1,800°F. The Vickers hardness of each alloy was measured, and microstructural changes were studied by scanning electron microscopy (SEM). Phase transformations were investigated by thermomechanical analysis (TMA). Heat treatment at 1,600° and 1,800°F significantly decreased the hardness of one Pd-Cu-Ga alloy, compared to the as-cast condition, as did heat treatment at 1,800°F for the other Pd-Cu-Ga alloy and one Pd-Ga alloy, and yielded fine-grained microstructures of the palladium solid solution. There were generally no significant changes in the hardness of the other Pd-Ga alloy for heat treatments over the entire temperature range, which was attributed to persistence of the as-cast dendritic structure. For all alloys, heat treatment at 1,200°F resulted in formation of discontinuous precipitates, which had very similar hardness to that of the palladium solid solution. Variations in the amount of a previously unidentified hard phase with temperature were assumed to account for the hardness variations in the harder Pd-Cu-Ga alloy. The TMA results suggested that a second-order phase transformation occurred around 1,050° to 1,400°F in all alloys, which may be formation of an ordered tweed structure observed by transmission electron microscopy in another study

    Effects of Solidification Conditions and Heat Treatment on the Microstructure and Vickers Hardness of Pd-Cu-Ga Dental Alloys

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    Two representative Pd-Cu-Ga dental alloys, one with a dendritic as-cast microstructure containing a eutectic interdendritic constituent and the other with an equiaxed fine-grained as-cast microstructure containing a near-surface eutectic constituent, have been subjected to rapid quenching following casting, in addition to the conventional bench cooling recommended by the manufacturers. The quenched alloys were subsequently heat treated at temperatures of 1200°, 1500° and 1800 op that span the range of the firing cycles for dental porcelain. Scanning electron microscopic examination showed that the lamellar eutectic constituents normally present in the microstructures of the as-cast and bench-cooled alloys persisted when the alloys were rapidly quenched after casting, although microstructural changes were evident. A large decrease occurred in the Vickers hardness of the alloy with the dendritic as-cast microstructure after heat treatment at 1500°F, and in the hardness of both alloys after heat treatment at 1800°F

    Characterization and Proteomic Analysis of <i>Geobacter sulfurreducens</i> PCA under Long-Term Electron-Donor Starvation

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    <div><p>ABSTRACT</p><p>The natural environment of <i>Geobacter sulfurreducens</i> is oligotrophic and described as limiting in both electron donors and terminal electron acceptors (TEA). In previous studies we examined the effects of long-term TEA (fumarate) limitation, and in this study we examine long-term batch cultures under limiting electron donor. The microorganism survived under long-term electron donor (acetate) starvation, maintaining a stable population of ∼1–2× 10<sup>8</sup> cells mL<sup>−1</sup>for >650 days. Proteins that varied in abundance with a high level of statistical significance (<i>p</i> < 0.05) for stages between mid-log to survival phase (acetate starved) were identified using iTRAQ based mass spectroscopy. The most highly represented proteins that significantly increased in level in the survival phase cells are generally membrane-associated and are involved in energy metabolism and protein fate. These results document that changes in the outer and cytoplasmic membranes may help <i>G. sulfurreducens</i> survive during starvation through detection and transport of nutrients into the cell. A sizeable portion of the identified proteins with unknown or hypothetical function further suggest that much of the biological process involved in survival have yet to be fully understood. <i>G. sulfurreducens</i> was also able to survive under long-term TEA-starvation conditions with ferric citrate as TEA and maintained a stable population of 1.5–3 × 10<sup>7</sup> cells mL<sup>−1</sup> for >650 days. We also found that survival phase cells from fumarate-limiting conditions were able to quickly resuscitate and reduce metal such as ferric iron as compared to the mid-log phase cells.</p></div

    Survival During Long-Term Starvation: Global Proteomics Analysis of <i>Geobacter sulfurreducens</i> under Prolonged Electron-Acceptor Limitation

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    The bioavailability of terminal electron acceptors (TEAs) and other substrates affects the efficiency of subsurface bioremediation. While it is often argued that microorganisms exist under “feast or famine”, in the laboratory most organisms are studied under “feast” conditions, whereas they typically encounter “famine” in nature. The work described here aims to understand the survival strategies of the anaerobe <i>Geobacter sulfurreduces</i> under TEA-starvation conditions. Cultures were starved for TEA and at various times sampled to perform global comparative proteomic analysis using iTRAQ to obtain insight into the dynamics of change in proteins/enzymes expression associated with change in nutrient availability/environmental stress. Proteins varying in abundance with a high level of statistical significance (<i>p</i> < 0.05) were identified to understand how cells change from midlog to (i) stationary phase and (ii) conditions of prolonged starvation (survival phase). The most highly represented and significantly up-regulated proteins in the survival phase cells are involved in energy metabolism, cell envelope, and transport and binding functional categories. The majority of the proteins were predicted to be localized in the cell membranes. These results document that changes in the outer and cytoplasmic membranes are needed for survival of <i>Geobacter</i> under starvation conditions. The cell shuts down anabolic processes and becomes poised, through changes in its membrane proteins, to sense nutrients in the environment, to transport nutrients into the cell, and to detect or utilize TEAs that are encountered. Under TEA-limiting conditions, the cells turned from translucent white to red in color, indicating higher heme content. The increase in heme content supported proteomics results showing an increase in the number of cytochromes involved in membrane electron transport during the survival phase. The cell is also highly reduced with minimal change in energy charge (ATP to total adenine nucleotide ratio). Nonetheless, these proteomic and biochemical results indicate that even under TEA starvation cells remain poised for bioremediation

    Metabolome-Wide Association Study of Primary Open Angle Glaucoma

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    PURPOSE. To determine if primary open-angle glaucoma (POAG) patients can be differentiated from controls based on metabolic characteristics. METHODS. We used ultra-high resolution mass spectrometry with C18 liquid chromatography for metabolomic analysis on frozen plasma samples from 72 POAG patients and 72 controls. Metabolome-wide Spearman correlation was performed to select differentially expressed metabolites (DEM) correlated with POAG. We corrected P values for multiple testing using Benjamini and Hochberg false discovery rate (FDR). Hierarchical cluster analysis (HCA) was used to depict the relationship between participants and DEM. Differentially expressed metabolites were matched to the METLIN metabolomics database; both DEM and metabolites significantly correlating with DEM were analyzed using MetaboAnalyst to identify metabolic pathways altered in POAG. RESULTS. Of the 2440 m/z (mass/charge) features recovered after filtering, 41 differed between POAG cases and controls at FDR ¼ 0.05. Hierarchical cluster analysis revealed these DEM to associate into eight clusters; three of these clusters contained the majority of the DEM and included palmitoylcarnitine, hydroxyergocalciferol, and high-resolution METLIN matches to sphingolipids, other vitamin D-related metabolites, and terpenes. MetaboAnalyst also indicated likely alteration in steroid biosynthesis pathways. CONCLUSIONS. Global ultrahigh resolution metabolomics emphasized the importance of altered lipid metabolism in POAG. The results suggest specific metabolic processes, such as those involving palmitoylcarnitine, sphingolipids, vitamin D-related compounds, and steroid precursors, may contribute to POAG status and merit more detailed study with targeted methods
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