241 research outputs found

    A forward speed effects study on jet noise from several suppressor nozzles in the NASA/Ames 40- by 80-foot wind tunnel

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    A test program was conducted in a 40 by 80 foot wind tunnel to evaluate the effect of relative velocity on the jet noise signature of a conical ejector, auxiliary inlet ejector, 32 spokes and 104 tube nozzle with and without an acoustically treated shroud. The freestream velocities in the wind tunnel were varied from 0 to 103.6 m/sec (300 ft/sec) for exhaust jet velocities of 259.1 m/sec (850 ft/sec) to 609.6 m/sec (2000 ft/sec). Reverberation corrections for the wind tunnel were developed and the procedure is explained. In conjunction with wind tunnel testing the nozzles were also evaluated on an outdoor test stand. The wind tunnel microphone arrays were duplicated during the outdoor testing. The data were then extrapolated for comparisons with data measured using a microphone array placed on a 30.5 meter (100 ft) arc. Using these data as a basis, farfield to nearfield arguments are presented with regards to the data measured in the wind tunnel. Finally, comparisons are presented between predictions made using existing methods and the measured data

    Effects of an Anabolic Implant and Transport on Metabolic Status and Muscle Traits of Feedlot Steers

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    A study was repeated over 2 years to determine the effect of feeding different levels of dry distillers grains with solubles (DDGS) and wet distillers grains with solubles (WDGS) on the performance of finishing cattle. In each year, 120 steers (756 ± 22 lb) were weighed, and randomly allocated to 15 pens. The pens were then assigned to one of five treatments: 1) corn-soybean meal (CON); 2) 20% DDGS; 3) 20% WDGS; 4) 40% DDGS; or 5) 40% WDGS. The basal diet consisted of 10% alfalfa hay, 4% molasses, 2% supplement, 10.5% SBM and 73.5% cracked corn. The WDGS and DDGS were added to replace all the SBM and part of the cracked corn. Steers were fed these diets for 138 and 129 days in years 1 and 2, respectively. Body weight was recorded prior to feeding at the start of the trial and every 28 days. Steers were harvested at a commercial facility and carcass data were collected. No treatment x year interactions occurred, thus data were pooled over the 2 years. There was an interaction between wet vs. dry and 20% vs. 40% distillers grains with solubles (DGS) for cumulative DMI. Steers fed 20% and 40% DDGS had the highest DMI, but feeding 40% WDGS significantly depressed (P \u3c 0.01) DMI. Cumulative ADG was similar across all treatments; however, steers fed 40% DGS had greater G:F (P \u3c 0.05) than those fed 20% DGS, and those fed WDGS were more efficient (P \u3c 0.01) than those fed DDGS. Pooled carcass data showed that steers fed DGS had greater (P \u3c 0.01) 12th rib fat compared to CON resulting in steers fed DGS having greater (P \u3c 0.05) Yield Grades compared to CON steers. Steers fed 20% DDGS and 20% WDGS had numerically higher (P \u3c 0.05) marbling scores compared to steers fed CON, 40% DDGS and 40% WDGS. Hot carcass weight, ribeye area, and percent kidney, pelvic, and heart fat were similar across all treatments. In conclusion, feeding DDGS and WDGS at 20 and 40% of the diet DM can be used to replace SBM in finishing diets to achieve similar gains and efficiencies. However, Yield Grades were greater for steers fed DGS compared to those fed the corn-soybean meal diet

    Identification of Genes Associated with Water Restriction Expressed in the Renal Cortex and Hypothalamus in Cattle

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    The short-term objective of this study is to discover genes associated with water restriction expressed in the renal cortex and hypothalamus in beef calves. The long-term goal is to understand genes and pathways important for thirst response in cattle. This knowledge may lead to discovery of genetic variants associated with water intake. Identification of animals with genetic potential to grow and thrive under drought conditions would be an asset to beef producers and communities which rely on beef production for a large part of their livelihoods. Both selected tissue types are known to be involved in response to hypertonicity (e.g., water restriction or dehydration)

    Cognitive impairment induced by delta9-tetrahydrocannabinol occurs through heteromers between cannabinoid CB1 and serotonin 5-HT2A receptors

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    Delta-9-tetrahydrocannabinol (THC), the main psychoactive compound of marijuana, induces numerous undesirable effects, including memory impairments, anxiety, and dependence. Conversely, THC also has potentially therapeutic effects, including analgesia, muscle relaxation, and neuroprotection. However, the mechanisms that dissociate these responses are still not known. Using mice lacking the serotonin receptor 5-HT2A, we revealed that the analgesic and amnesic effects of THC are independent of each other: while amnesia induced by THC disappears in the mutant mice, THC can still promote analgesia in these animals. In subsequent molecular studies, we showed that in specific brain regions involved in memory formation, the receptors for THC and the 5-HT2A receptors work together by physically interacting with each other. Experimentally interfering with this interaction prevented the memory deficits induced by THC, but not its analgesic properties. Our results highlight a novel mechanism by which the beneficial analgesic properties of THC can be dissociated from its cognitive side effects

    Cruciferous vegetable supplementation in a controlled diet study alters the serum peptidome in a GSTM1-genotype dependent manner

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    <p>Abstract</p> <p>Background</p> <p>Cruciferous vegetable intake is inversely associated with the risk of several cancers. Isothiocyanates (ITC) are hypothesized to be the major bioactive constituents contributing to these cancer-preventive effects. The polymorphic glutathione-<it>S</it>-transferase (GST) gene family encodes several enzymes which catalyze ITC degradation <it>in vivo</it>.</p> <p>Methods</p> <p>We utilized high throughput proteomics methods to examine how human serum peptides (the "peptidome") change in response to cruciferous vegetable feeding in individuals of different <it>GSTM1 </it>genotypes. In two randomized, crossover, controlled feeding studies (EAT and 2EAT) participants consumed a fruit- and vegetable-free basal diet and the basal diet supplemented with cruciferous vegetables. Serum samples collected at the end of the feeding period were fractionated and matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry spectra were obtained. Peak identification/alignment computer algorithms and mixed effects models were used to analyze the data.</p> <p>Results</p> <p>After analysis of spectra from EAT participants, 24 distinct peaks showed statistically significant differences associated with cruciferous vegetable intake. Twenty of these peaks were driven by their <it>GSTM1 </it>genotype (i.e., <it>GSTM1+ </it>or <it>GSTM1- </it>null). When data from EAT and 2EAT participants were compared by joint processing of spectra to align a common set, 6 peaks showed consistent changes in both studies in a genotype-dependent manner. The peaks at 6700 <it>m/z </it>and 9565 <it>m/z </it>were identified as an isoform of transthyretin (TTR) and a fragment of zinc α2-glycoprotein (ZAG), respectively.</p> <p>Conclusions</p> <p>Cruciferous vegetable intake in <it>GSTM1+ </it>individuals led to changes in circulating levels of several peptides/proteins, including TTR and a fragment of ZAG. TTR is a known marker of nutritional status and ZAG is an adipokine that plays a role in lipid mobilization. The results of this study present evidence that the <it>GSTM1</it>-genotype modulates the physiological response to cruciferous vegetable intake.</p

    Selective inhibitors of cardiac ADPR cyclase as novel anti-arrhythmic compounds

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    ADP-ribosyl cyclases (ADPRCs) catalyse the conversion of nicotinamide adenine dinucleotide to cyclic adenosine diphosphoribose (cADPR) which is a second messenger involved in Ca2+ mobilisation from intracellular stores. Via its interaction with the ryanodine receptor Ca2+ channel in the heart, cADPR may exert arrhythmogenic activity. To test this hypothesis, we have studied the effect of novel cardiac ADPRC inhibitors in vitro and in vivo in models of ventricular arrhythmias. Using a high-throughput screening approach on cardiac sarcoplasmic reticulum membranes isolated from pig and rat and nicotinamide hypoxanthine dinuleotide as a surrogate substrate, we have identified potent and selective inhibitors of an intracellular, membrane-bound cardiac ADPRC that are different from the two known mammalian ADPRCs, CD38 and CD157/Bst1. We show that two structurally distinct cardiac ADPRC inhibitors, SAN2589 and SAN4825, prevent the formation of spontaneous action potentials in guinea pig papillary muscle in vitro and that compound SAN4825 is active in vivo in delaying ventricular fibrillation and cardiac arrest in a guinea pig model of Ca2+ overload-induced arrhythmia. Inhibition of cardiac ADPRC prevents Ca2+ overload-induced spontaneous depolarizations and ventricular fibrillation and may thus provide a novel therapeutic principle for the treatment of cardiac arrhythmias

    Activation Status of Wnt/ß-Catenin Signaling in Normal and Neoplastic Breast Tissues: Relationship to HER2/neu Expression in Human and Mouse

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    Wnt/ß-catenin signaling is strongly implicated in neoplasia, but the role of this pathway in human breast cancer has been controversial. Here, we examined Wnt/ß-catenin pathway activation as a function of breast cancer progression, and tested for a relationship with HER2/neu expression, using a human tissue microarray comprising benign breast tissues, ductal carcinoma in situ (DCIS), and invasive carcinomas. Cores were scored for membranous ß-catenin, a key functional component of adherens junctions, and for nucleocytoplasmic ß-catenin, a hallmark of Wnt/ß-catenin pathway activation. Only 82% of benign samples exhibited membrane-associated ß-catenin, indicating a finite frequency of false-negative staining. The frequency of membrane positivity was similar in DCIS samples, but was significantly reduced in carcinomas (45%, P<0.001), consistent with loss of adherens junctions during acquisition of invasiveness. Negative membrane status in cancers correlated with higher grade (P = 0.04) and estrogen receptor-negative status (P = 0.03), both indices of poor prognosis. Unexpectedly, a substantial frequency of nucleocytoplasmic ß-catenin was observed in benign breast tissues (36%), similar to that in carcinomas (35%). Positive-staining basal nuclei observed in benign breast may identify putative stem cells. An increased frequency of nucleocytoplasmic ß-catenin was observed in DCIS tumors (56%), suggesting that pathway activation may be an early event in human breast neoplasia. A correlation was observed between HER2/neu expression and nucleocytoplasmic ß-catenin in node-positive carcinomas (P = 0.02). Furthermore, cytoplasmic ß-catenin was detected in HER2/neu-induced mouse mammary tumors. The Axin2NLSlacZ mouse strain, a previously validated reporter of mammary Wnt/ß-catenin signaling, was utilized to define in vivo transcriptional consequences of HER2/neu-induced ß-catenin accumulation. Discrete hyperplastic foci observed in mammary glands from bigenic MMTV/neu, Axin2NLSlacZ mice, highlighted by robust ß-catenin/TCF signaling, likely represent the earliest stage of mammary intraepithelial neoplasia in MMTV/neu mice. Our study thus provides provocative evidence for Wnt/ß-catenin signaling as an early, HER2/neu-inducible event in breast neoplasia
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