615 research outputs found

    EFFECTS OF ENDOPHYTE INFECTED FESCUE ALKALOID INGESTION ON ENERGY METABOLISM, NITROGEN BALANCE, IN SITU FEED DEGRADATION, AND RUMINAL PASSAGE RATES

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    The decrease in productivity caused by fescue toxicosis has been estimated to cost the United States livestock industry more than $1 billion per year due to reduced growth and diminished reproductive efficiency. This goal of the research presented in this dissertation is to enhance the knowledge base concerning the underlying physiological changes that occur during fescue toxicosis that lead to reduced intake and weight gain in cattle. As one of the factors associated with fescue toxicosis is a reduction in feed intake, achieving a consistent and adequate intake of toxins can be a complication. Results from experiment 1demonstrate that ruminal dosing of ground seed and a seed extract are able to mimic the classic symptoms of fescue toxicosis in cattle. This model whereby seed or extract is directly dosed into the rumen eliminates the possibility of reduced alkaloid intake due to refusal of feed by the animal. This model allows for more precise and repeatable dosing of alkaloids in fescue research. Experiment 2 results indicate that ingestion of endophyte-infected tall fescue leads to decreased fasting heat production in cattle. This is indicative of a reduction in maintenance energy requirements and may be related to a decrease in liver size or other metabolic activity in animals grazing endophyte-infected pastures. In addition, a reduction in basal metabolic rate may cause the compensatory gain often observed in cattle entering the feedlot after grazing endophyte-infected pastures. Data from experiment 3 provides evidence that whole body nitrogen and energy metabolism are not altered by fescue alkaloid ingestion. Experiment 3 also addresses the rate of feed degradation and ruminal passage rates in cattle ingesting endophyte infected fescue. While ruminal VFA profile is altered, this is likely due to reduced absorption, not increased production. The data from this experiment indicate that the reduction in weight gain and productivity seen during fescue toxicosis is primarily a function of reduced intake and not secondary effects of alkaloid ingestion

    Method of making a membrane having hydrophilic and hydrophobic surfaces for adhering cells or antibodies by using atomic oxygen or hydroxyl radicals

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    A portion of an organic polymer article such as a membrane is made hydrophilic by exposing a hydrophobic surface of the article to a depth of about 50 to about 5000 angstroms to atomic oxygen or hydroxyl radicals at a temperature below 100C., preferably below 40 C, to form a hydrophilic uniform surface layer of hydrophilic hydroxyl groups. The atomic oxygen and hydroxyl radicals are generated by a flowing afterglow microwave discharge, and the surface is outside of a plasma produced by the discharge. A membrane having both hydrophilic and hydrophobic surfaces can be used in an immunoassay by adhering antibodies to the hydrophobic surface. In another embodiment, the membrane is used in cell culturing where cells adhere to the hydrophilic surface. Prior to adhering cells, the hydrophilic surface may be grafted with a compatibilizing compound. A plurality of hydrophilic regions bounded by adjacent hydrophobic regions can be produced such that a maximum of one cell per each hydrophilic region adheres

    River otters of the Green-Duwamish: biomonitors of ecological health

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    River otters (Lontra canadensis) are apex predators that play an important role in aquatic ecosystems. They accumulate contaminants via their diet of fish and invertebrates, potentially serving as biomonitors of watershed health. In summer and fall 2016, we collected 33 otter scats from sites along the Green-Duwamish River, ranging from river miles 0-54. River miles 0-5 represent the Lower Duwamish Waterway (LDW), a U.S. Superfund site slated for a 17-year remediation. Concentrations of polychlorinated biphenyls (PCBs) at sites in the LDW were 9.1 and 19.3 mg/kg (geometric means, lipid weight) - above the reported threshold value of 9 mg/kg associated with adverse effects for river otters. By river mile 10, mean concentrations of PCBs decreased to 2.6 mg/kg, with remaining upriver sites ranging from 0.4-1.9 mg/kg. Polycyclic aromatic hydrocarbon (PAH) concentrations showed a similar pattern. The highest PAH levels (140 and 91 mg/kg, geometric means, wet weight) were measured in the LDW whereas levels upriver were 9.7-25 mg/kg. Based on preliminary genetics data from several sampling locations, we infer that otters remain in local river reaches, so scat contaminant levels reflect local environmental concentrations. These are the only empirical contaminant data available for a mammal or apex predator in the Green-Duwamish, and they reveal: 1) otters may be impacted by contaminant loads in the LDW; 2) the contamination gradient along the Green-Duwamish is reflected in otters, indicating they may be useful biomonitors; and 3) a baseline level of contamination in otters that may be of great value for assessing ecological impacts of long-term cleanup efforts. Scat collected in 2017 and analyses for brominated flame retardants, organochlorine pesticides, stable isotopes, and genetics will provide additional depth and breadth to these results. Significant questions remain as to the potential individual health and population impacts of environmental contaminants in this top-level aquatic predator

    LEAKAGE CHARACTERISTICS OF OPENINGS FOR REACTOR HOUSING COMPONENTS

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    Measurements were made of the air leakage rates through structural components that penetrate semicontainment reactor housing installations. Full- sized test specimens were sealed inside a 10-ft-diameter test sphere, and the leakage rate was measured as a function of pressure for pressure differentials of up to 25 in. of water. The data were fitted to empirical equations that describe the leak rate at any pressure differential within the range of the experimental tests. The forms of the equations are such that the total leak rate of a building can be obtained by summing the empirical constants and multiplying by a probable pressure differential. (auth

    A case of primary renal angiosarcoma

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    A 78-year old man was diagnosed with a left bleeding renal cyst from CT scan results. Serial CT scans revealed the left kidney mass to be increasing in size and a new lesion in the liver. Renal cell carcinoma with liver metastasis was diagnosed and a radical nephrectomy performed. The initial pathological diagnosis was a benign chronic hematoma. However, the liver mass increased in size and multiplied, while another mass emerged in the twelfth thoracic vertebra with spinal paralysis and was immediately removed. Pathological findings for that specimen showed malignancy of stromal cell origin but low atypia. The renal specimen was re-evaluated using whole cross-section analysis and immunohistochemistry, and diagnosed as a primary renal angiosarcoma. Recombinant interleukin-2 therapy was started immediately; however, the patient died of metastatic disease 13 months after the initial operation. Although contrast imaging depicted the primary lesion as a non-specific hematoma with little focal pooling, and low-grade cytological atypia was shown pathologically, the angiosarcoma was extremely aggressive

    Evaluation of antimicrobial effectiveness of pimaricin-loaded thermosensitive nanohydrogels in grape juice

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    Pimaricin-loaded poly(N-isopropylacrylamide) nanohydrogels with and without acrylic acid, were evaluated as food-spoilage inhibitors in a model system and a real food product: grape juice. Pimaricin was proposed as a non-allergenic alternative to sulphites for protecting juices against recontamination. However, pimaricin may degrade under conditions and treatments (heating, acidification, lighting) commonly applied in producing fresh juices. Nanohydrogel encapsulation may be a feasible procedure to avoid pimaricin degradation, improving its antimicrobial activity. Pimaricin-free nanohydrogels did not affect the growth of the indicator yeast either in the food model system or in grape juice. Conversely, pimaricin-loaded nanohydrogels effectively inhibited the growth of the indicator yeast. In some cases, the inhibition was extended even further than using free pimaricin. For instance, in the food model system, pimaricin-loaded nanohydrogels with acrylic acid (NPPNIPA-20AA(5)) prevented the yeast growth for more than 81 h while free pimaricin was only effective for 12 h. Despite pimaricin-loaded nanohydrogels without acrylic acid (NPPNIPA(5)) were able to reduce maximum yeast growth, as in all treatments with pimaricin, the extent of the inhibitory effect was not significantly (p>0.05) different to that achieved with free pimaricin. In grape juice, both free pimaricin and NPPNIPA-20AA(5) treatment completely inhibited the growth of the indicator yeast until the end of the bioassay. However, the latter provided similar inhibition levels using a smaller amount of pimaricin due to PNIPA-20AA(5) protection and its controlled release from the nanohydrogel. Therefore, nanohydrogel encapsulation may help to optimise antifungal treatments and decrease the incidence of food allergies.Funded by grant (MAT 2006-11662-CO3-CO2-C01/MAT 2010-21509-C03-01/EUI 2008-00115) from the “Ministerio de Educación y Ciencia” (Spain). Grant (SFRH/BPD/87910/2012) from the Fundação para a Ciência e Tecnologia (FCT, Portugal). Marie Curie COFUND Postdoctoral Research Fellow

    Expanding the Y Dwarf Census with Spitzer Follow-up of the Coldest CatWISE Solar Neighborhood Discoveries

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    We present Spitzer 3.6 and 4.5 μm follow-up of 170 candidate extremely cool brown dwarfs newly discovered via the combination of Wide-field Infrared Survey Explorer (WISE) and NEOWISE imaging at 3–5 μm. CatWISE, a joint analysis of archival WISE and NEOWISE data, has improved upon the motion measurements of AllWISE by leveraging a >10× time baseline enhancement, from 0.5 yr (AllWISE) to 6.5 yr (CatWISE). As a result, CatWISE motion selection has yielded a large sample of previously unrecognized brown dwarf candidates, many of which have archival detections exclusively in the WISE 4.6 μm (W2) channel, suggesting that they could be both exceptionally cold and nearby. Where these objects go undetected in WISE W1 (3.4 μm), Spitzer can provide critically informative detections at 3.6 μm. Of our motion-confirmed discoveries, 17 have a best-fit Spitzer [3.6]–[4.5] color most consistent with spectral type Y. It is likely that CWISEP J144606.62–231717.8 (μ ≈ 1.”3 yr⁻¹) is the reddest, and therefore potentially coldest, member of our sample with a very uncertain [3.6]–[4.5] color of 3.71 ± 0.44 mag. We also highlight our highest proper-motion discovery, WISEA J153429.75–104303.3, with μ ≈ 2.”7 yr⁻¹. Given that the prior list of confirmed and presumed Y dwarfs consists of just 27 objects, the Spitzer follow-up presented in this work has substantially expanded the sample of identified Y dwarfs. Our new discoveries thus represent significant progress toward understanding the bottom of the substellar mass function, investigating the diversity of the Y dwarf population, and selecting optimal brown dwarf targets for James Webb Space Telescope spectroscopy
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