1,005 research outputs found

    Characteristics of hingeless rotors with hub moment feedback controls including experimental rotor frequency response, Volume 1

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    Wind tunnel tests to determine the dynamic characteristics of hingeless rotors with hub moment feedback controls and to acquire experimental hingeless rotor transfer functions are discussed. Rotor transfer functions were calculated from data acquired during open loop frequency response tests. The transfer functions are linear and present the rotor longitudinal and lateral frequency responses to collective pitch, longitudinal cyclic pitch, and lateral cyclic pitch. The theoretical analysis was based on the rigid blade flapping model coupled with appropriate control system and cyclic pitch actuator equations of motion

    Research program to determine rotor response characteristics at high advance ratios Final report

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    Stability and response characteristics of directly controlled rigid rotors at high advance ratios and correlation of mathematical model with wind tunnel test dat

    Some non-revisionist solutions to some semantic antinomies

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    Addendum to the MyPyramid Equivalents Database 2.0

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    AbstractBackgroundThe MyPyramid Equivalents Database (MPED) provides amounts of food groups and subgroups in foods consumed in nationwide food consumption surveys. The most recent MPED issued by the Agricultural Research Service (ARS) was Version 2.0, created for use with the National Health and Nutrition Examination Survey (NHANES) 2003-04. Several of the Center for Nutrition Policy and Promotion's (CNPP) projects require food group equivalents data for foods from more recent NHANES.ObjectiveTo provide a supplementary database of food group equivalents for more recent NHANES foods, for use in CNPP projects.DescriptionAdditional foods (n=820) reported in NHANES 2005-06 and 2007-08 were identified for inclusion in several CNPP projects, including the new online diet assessment tool, the SuperTracker. Cup and ounce equivalents were calculated for 750 foods by using the approach described in the documentation for the MPED 2.0. The USDA National Nutrient Database for Standard Reference, Release 23 (2010) was used for calculations. ARS provided equivalents data for 70 formulated foods. The Addendum to the MPED includes cup or ounce equivalents per 100 grams of food for each USDA food group and subgroup, grams of discretionary solid fats and oils, teaspoons of added sugars, alcoholic beverages, as well as whole fruit and fruit juice equivalents. The Addendum database and documentation are available on the CNPP web site at: http://www.cnpp.usda.gov/OtherProjects.htm.ConclusionThe Addendum provides useful data for foods from more recent NHANES that are not in MPED 2.0. It will be available until the next equivalents database is released by ARS

    Cyclic AMP Inhibits Secretion From Electroporated Human Neutrophils

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    It has long been known that Intracellular cAMP inhibits and cGMP enhances intact neutrophil function. However, these effects are modest and require relatively high concentrations of the cyclic nucleotides. We decided to re‐examine the effects of cyclic nucleotides on Ca2+‐induced secretion by electroporated cells. This system allowed us to bypass normal cell surface receptor‐ligand interactions as well as to directly expose the intracellular space to native cyclic nucleotides. We found that concentrations of cAMP as low as 3 μM inhibited Ca2+‐induced secretion; 30–300 μM cAMP was maximally inhibitory. cAMP was actually slightly more potent than dibutyryl cAMP, a membrane‐permeant derivative. In contrast, cGMP was only slightly stimulatory at 3 μM and modestly inhibitory at 300 μM; dibutyryl cGMP was ineffective. A more detailed investigation of the effects of cAMP showed that inhibition was only obtained in the presence of Mg2+. Half‐maximal inhibition by cAMP occurred at 10–30 μM. Inhibition by cAMP was achieved by shifting the Ca2+ dose‐response curve for secretion to the right; this was observed for the release of both specific granules (vitamin B12 binding protein) and azurophil granules (B‐glucuronidase). We previously showed that ATP could enhance Ca2+‐induced secretion in the presence of Mg2+, apparently by interacting with a cell surface purine receptor. However, increasing concentrations of ATP could not overcome inhibition by cAMP; this suggested that cAMP acted at some site other than the purine receptor. Inhibition by cAMP was also less apparent in the presence of the protein kinase C agonist phorbol myristate acetate (PMA), suggesting that the cyclic nucleotide did not produce systemic desensitization of the neutrophils. In summary, these results demonstrate that low, physiologically relevant concentrations of cAMP can modulate neutrophil responsiveness.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141578/1/jlb0172.pd

    A Microstructure Sensitive Approach for the Prediction of the Creep Behaviour and Life under Complex Loading Paths

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    The prediction of the creep behaviour and life of components of aeronautic engines like high pressure turbine blades is still a challenging issue due to non-isothermal loadings. Indeed, certification procedures of turboshaft engines for helicopters consist of complex thermomechanical histories, sometimes including short and very high temperature excursions close to the γ’-solvus (T~1200°C) of the blade alloy. A better design of those components could be gained using a model that takes into account non-isothermal loadings inducing microstructural changes. Most of the commonly used models consider only a nearly constant (or slowly evolving) microstructure, i.e. far from the rapid microstructure evolutions encountered during close γ’-solvus overheatings where a rapid dissolution/precipitation of the γ’-phase and fast recovery mechanisms were observed by Cormier et al. (2007b). A new constitutive modelling approach was hence recently proposed in a crystal viscoplasticity framework to capture the transient effects of such rapid microstructure evolutions on the creep behaviour and life (Cormier and Cailletaud (2010a)). In this article, an updated version of this model is detailed. Special attention will be paid to (i) the effect of the accumulated plastic strain on the microstructure evolution, (ii) the introduction of an additional damage formulation, and (iii) the creep strain at failure. The performances of the model are illustrated on the basis of isothermal or complex non-isothermal creep experiments performed on nearly [001] oriented samples

    Food Characterization of the Spotted Pimelodid Fish Pimelodus Maculatus From a Polluted Urban River in Argentina

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    On the present study, the nourishment and the digestive system of a population of the spotted pimelodid Pimelodus maculatus Lacepède 1803 from a polluted urban river in Argentina were analyzed (Reconquista River, Buenos Aires province). The specimens are characterized by having benthic habits and an omnivore diet. In their intestinal content, a diversity of components was identified. Such components were grouped into ten alimentary items, with dietary variations according to body size while the longitude of the intestine remained proportional to standard length. Microbiological analysis in the gills, stomach and intestine showed the occurrence of Staphylococcus aureus, Escherichia coli and Salmonella sp. Fungi and yeast were also detected. Bacterial accounts were very high both in the analyzed organs as well in water samples. The ecological and sanitary significance of the identified bacteria is discussed

    Intercellular adhesion molecule-1 expression in human endometrium: implications for long term progestin only contraception

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    BACKGROUND: Neutrophils infiltrate the endometrium pre-menstrually and after long-term progestin only-contraceptive (LTPOC) treatment. Trafficking of neutrophils involves endothelial cell-expressed intercellular adhesion molecule (ICAM-1). Previous studies observed that ICAM-1 was immunolocalized to the endothelium of endometrial specimens across the menstrual cycle, but disagreed as to whether extra-endothelial cell types express ICAM-1 and whether ICAM-1 expression varies across the menstrual cycle. METHODS: Endometrial biopsies were obtained from women across the menstrual cycle and from those on LTPOC treatment (either Mirena or Norplant). The biopsies were formalin-fixed and paraffin-embedded with subsequent immunohistochemical staining for ICAM-1. RESULTS: The current study found prominent ICAM-1 staining in the endometrial endothelium that was of equivalent intensity in different blood vessel types irrespective of the steroidal or inflammatory endometrial milieu across the menstrual cycle and during LTPOC therapy. Unlike the endothelial cells, the glands were negative and the stromal cells were weakly positive for ICAM immunostaining. CONCLUSION: The results of the current study suggest that altered expression of ICAM-1 by endothelial cells does not account for the influx of neutrophils into the premenstrual and LTPOC-derived endometrium. Such neutrophil infiltration may depend on altered expression of neutrophil chemoattractants
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