943 research outputs found

    Ranger VII photographic parameters

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    Tables of computer generated photographic parameters necessary for detailed interpretation of Ranger VII television camera pictures - trajectory and time-to-impact dat

    Exploratory analysis of the determinants of audit engagement resource allocations

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    https://egrove.olemiss.edu/dl_proceedings/1051/thumbnail.jp

    Toxicity of Ammonia and Nitrite to Aquatic Macroinvertebrates

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    The acute toxicity of ammonia was studied for six aquatic macroinvertebrate species (mayfly, stonefly, and caddisfly families). Two partial-chronic (24- and 30-day) tests were conducted on Pteronarcella badia. The acute toxicity of nitrite was studied for seven species, including one Diptera species; the mitigating effect of chloride ion on nitrite toxicity to two species was also investigated. For 6 tests on ammonia the median lethal concentration (96-hour LC50) values ranged from 1.8 to 5.0 mg/L un-ionized ammonia (NH3); in 19 tests less than 50% of the larvae died at the highest test concentration, so an LC50 could not be calculated. In the partial-chronic tests on P. badia, food consumption was not affected at concentrations up to 6.9 mg/L NH3, but concentrations in excess of 3.4 mg/L NH3 adversely affected nymphal survival rates and emergence of adults. For nitrite toxicity, test results showed a wide range of tolerance. The 96-hour LC50 for the single species of Diptera exceeded 123 mg/liter NO2-N; the 96-hour LC50 range for the other tests was between 0.25 and 2.4 mg/liter NO2-N. The addition of 10 mg/liter chloride ion in nitrite tests on P. badia and Ephemerella grandis resulted in a 3- to 10-fold decrease in 96-hour LC50 values. The tolerance to ammonia of the most sensitive of the insect species tested was greater than that reported in the literature for most species of fishes. Except for A. variegata, the range of acute toxicity of nitrite to the insects tested was similar to that reported for fishes

    Oxidized flavors in strawberry ice cream

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    At the time this project was initiated only a small amount of material had been published concerning this defect and even that was subject to considerable controversy. That the defect under consideration is important has been emphasized by other workers and needs no reiteration here. It was the opinion of the authors that the study should be made with ice cream manufactured in a commercial manner and from commercial products. This was done wherever possible. The objectives of the project were to attempt to determine which single factor or group of the following possible factors-oxidases in the fruit, copper and iron in the mix, strawberries and types of added solids - was responsible for the occurrence of the defect. It was likewise considered advisable to see whether or not such changes as occur in the fat, if the defect were a fat oxidation, were sufficient to cause detectable variations in the iodine, acetyl and Reichert- Meissl numbers of the fat of the ice cream

    Rootstock influences postharvest anthracnose development in 'Hass' avocado

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    Rootstock studies conducted on ‘Hass’ avocado found that rootstock had a significant impact on postharvest anthracnose susceptibility. This is the first record of such an effect for avocado. The severity and incidence of anthracnose was significantly lower on ‘Hass’ grafted to ‘Velvick’ Guatemalan seedling rootstock compared with the ‘Duke 6’ Mexican seedling rootstock. Differences in anthracnose susceptibility were related to significant differences in concentrations of antifungal dienes in the leaves and mineral nutrients in the leaves and fruits from trees grafted to different rootstocks. Leaf diene concentrations were up to 1.5 times higher in ‘Hass’ trees on the ‘Velvick’ than the ‘Duke 6’ rootstock. In ungrafted nursery stock trees, diene concentrations were around 3 times higher in ‘Velvick’ than ‘Duke 6’ leaves. The ‘Velvick’/‘Hass’ combination also had a significantly lower leaf N concentration, a significantly higher fruit flesh Mn concentration, and significantly lower and higher leaf N/Ca and Ca+Mg/K ratios, respectively. A significant correlation (r = 0.82) between anthracnose severity and skin N/Ca ratio was also evident

    Novel translocation responses of cytosolic phospholipase A2α fluorescent proteins

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    AbstractCytosolic phospholipase A2 (cPLA2)α responds to the rise in cytosolic Ca2+ ([Ca2+]i) attending cell stimulation by moving to intracellular membranes, releasing arachidonic acid (AA) from these membranes, and thereby initiating the synthesis of various lipid mediators. Under some conditions, however, cPLA2α translocation occurs without any corresponding changes in [Ca2+]i. The signal for such responses has not been identified. Using confocal microscopy to track fluorescent proteins fused to cPLA2α or cPLA2α's C2 domain, we find that AA mimics Ca2+ ionophores in stimulating cPLA2α translocations to the perinuclear ER and to a novel site, the lipid body. Unlike the ionophores, AA acted independently of [Ca2+]i rises and did not translocate the proteins to the Golgi. AA's action did not involve its metabolism to eicosanoids or acylation into cellular lipids. Receptor agonists also stimulated translocations targeting lipid bodies. We propose that AA is a signal for Ca2+-independent cPLA2α translocation and that lipid bodies are common targets of cPLA2α and contributors to stimulus-induced lipid mediator synthesis

    Impact of Dietetic Intervention on Skin Autofluorescence and Nutritional Status in Persons Receiving Dialysis: A Proof of Principle Study

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    Objective: Advanced glycation end-products (AGEs) are uremic toxins that result from oxidative stress and food consumption. We have previously reported that markers of malnutrition are more important determinants of increased skin autofluorescence (SAF), a measure of AGE accumulation and risk factor for mortality, than high dietary AGE intake in a hemodialysis (HD) population, suggesting that correcting malnutrition may decrease SAF. Design and methods: We investigated this hypothesis in a single center, non-randomized proof of principle study. We enrolled 27 HD and one peritoneal dialysis (PD) patient with malnutrition who received individualized nutritional advice and support over 6 months. SAF was measured at baseline, 3 and 6 months. Dietary intake and nutritional status were assessed at baseline and 6 months. Results were compared with a control group of malnourished dialysis patients (n= 41 HD and 8 PD) from a previous observational study

    Cancer resistance of SR/CR mice in the genetic knockout backgrounds of leukocyte effector mechanisms: determinations for functional requirements

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    <p>Abstract</p> <p>Background</p> <p>Spontaneous Regression/Complete Resistant (SR/CR) mice are a colony of cancer-resistant mice that can detect and rapidly destroy malignant cells with innate cellular immunity, predominately mediated by granulocytes. Our previous studies suggest that several effector mechanisms, such as perforin, granzymes, or complements, may be involved in the killing of cancer cells. However, none of these effector mechanisms is known as critical for granulocytes. Additionally, it is unclear which effector mechanisms are required for the cancer killing activity of specific leukocyte populations and the survival of SR/CR mice against the challenges of lethal cancer cells. We hypothesized that if any of these effector mechanisms was required for the resistance to cancer cells, its functional knockout in SR/CR mice should render them sensitive to cancer challenges. This was tested by cross breeding SR/CR mice into the individual genetic knockout backgrounds of perforin (Prf<sup>-/-</sup>), superoxide (Cybb<sup>-/</sup>), or inducible nitric oxide (Nos2<sup>-/</sup>).</p> <p>Methods</p> <p>SR/CR mice were bred into individual Prf<sup>-/-</sup>, Cybb<sup>-/-</sup>, or Nos2<sup>-/- </sup>genetic backgrounds and then challenged with sarcoma 180 (S180). Their overall survival was compared to controls. The cancer killing efficiency of purified populations of macrophages and neutrophils from these immunodeficient mice was also examined.</p> <p>Results</p> <p>When these genetically engineered mice were challenged with cancer cells, the knockout backgrounds of Prf<sup>-/-</sup>, Cybb<sup>-/-</sup>, or Nos2<sup>-/- </sup>did not completely abolish the SR/CR cancer resistant phenotype. However, the Nos2<sup>-/- </sup>background did appear to weaken the resistance. Incidentally, it was also observed that the male mice in these immunocompromised backgrounds tended to be less cancer-resistant than SR/CR controls.</p> <p>Conclusion</p> <p>Despite the previously known roles of perforin, superoxide or nitric oxide in the effector mechanisms of innate immune responses, these effector mechanisms were not required for cancer-resistance in SR/CR mice. The resistance was functional when any one of these effector mechanisms was completely absent, except some noticeably reduced penetrance, but not abolishment, of the phenotype in the male background in comparison to female background. These results also indicate that some other effector mechanism(s) of granulocytes may be involved in the killing of cancer cells in SR/CR mice.</p
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