511 research outputs found

    Generating a Reduced Gravity Environment on Earth

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    The Active Response Gravity Offload System (ARGOS) is designed to simulate reduced gravity environments, such as Lunar, Martian, or microgravity using a vertical lifting hoist and horizontal motion system. Three directions of motion are provided over a 41 ft x 24 ft x 25 ft tall area. ARGOS supplies a continuous offload of a portion of a person's weight during dynamic motions such as walking, running, and jumping. The ARGOS system tracks the person's motion in the horizontal directions to maintain a vertical offload force directly above the person or payload by measuring the deflection of the cable and adjusting accordingly

    Gastrocnemius Mass Is Lower 28 Days After Recovery From A Cycle Of Cisplatin In Mice

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    Platinum-based chemotherapeutic agents, such as cisplatin, are widely employed as a primary treatment modality for various cancer types. Despite their efficacy, cisplatin\u27s mechanism of action involves inducing DNA damage in cells, leading to pronounced acute and long-term side effects. One well established side effect is rapid loss in muscle mass. However, very little is known about the long-term effects of chemotherapy treatment on muscle size. PURPOSE: of this study was to analyze the long-term effects of cisplatin on muscle mass recovery. We hypothesized that cisplatin would have a negative long-term effect on muscle recovery. METHODS: 5-6 month-old CD2F1 mice were divided into two groups receiving injections of either Cisplatin (Cis) or Vehicle (Veh); n = 10 per group. A clinically relevant chemotherapy cycle was completed by a once weekly injection of 5mg/kg body weight of cisplatin for four weeks. Veh mice received an equal volume of saline. Following the cycle, mice recovered in their cage for 28 days and then hindlimb muscles were taken. Data were analyzed using independent t-test and presented as mean ± standard error. RESULTS: The gastrocnemius mass was significantly lower (p=0.008) in cisplatin-treated mice (139.20 ± 4.98) compared to the vehicle-treated group (147.50 ± 2.26). Conversely, the soleus did not show a significant difference (p=0.756) between Cis (9.90 ± 0.46) and Veh (10.10 ± 0.44) groups. Similarly, the Plantaris did not demonstrate a significant difference (p=0.950) in Cis treatment (18.65 ± 0.57) compared to Veh (18.65 ± 0.54). CONCLUSION: These data indicate a diminished ability of the gastrocnemius, the primary hindlimb flexor, to recover after a bout of cisplatin drug treatment. Further research is needed to better understand the mechanisms behind muscle specific differences and failed muscle mass recovery in the gastrocnemius

    The Upper Crustal Evolution of a Large Silicic Magma Body: Evidence from Crystal-scale Rb-Sr Isotopic Heterogeneities in the Fish Canyon Magmatic System, Colorado

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    Batholith-sized bodies of crystal-rich magmatic ‘mush' are widely inferred to represent the hidden sources of many large-volume high-silica rhyolite eruptive units. Occasionally these mush bodies are ejected along with their trapped interstitial liquid, forming the distinctive crystal-rich ignimbrites known as ‘monotonous intermediates'. These ignimbrites are notable for their combination of high crystal contents (35-55%), dacitic bulk compositions with interstitial high-silica rhyolitic glass, and general lack of compositional zonation. The 5000 km3 Fish Canyon Tuff is an archetypal eruption deposit of this type, and is the largest known silicic eruption on Earth. Ejecta from the Fish Canyon magmatic system are notable for the limited compositional variation that they define on the basis of whole-rock chemistry, whereas ∼ 45 vol. % crystals in a matrix of high-silica rhyolite glass together span a large range of mineral-scale isotopic variability (microns to millimetres). Rb/Sr isotopic analyses of single crystals (sanidine, plagioclase, biotite, hornblende, apatite, titanite) and sampling by micromilling of selected zones within glass plus sanidine and plagioclase crystals document widespread isotopic disequilibrium at many scales. High and variable 87Sr/86Sri values for euhedral biotite grains cannot be explained by any model involving closed-system radiogenic ingrowth, and they are difficult to rationalize unless much of this radiogenic Sr has been introduced at a late stage via assimilation of local Proterozoic crust. Hornblende is the only phase that approaches isotopic equilibrium with the surrounding melt, but the melt (glass) was isotopically heterogeneous at the millimetre scale, and was therefore apparently contaminated with radiogenic Sr shortly prior to eruption. The other mineral phases (plagioclase, sanidine, titanite, and apatite) have significantly lower 87Sr/86Sri values than whole-rock values (as much as −0·0005). Such isotopic disequilibrium implies that feldspars, titanite and apatite are antecrysts that crystallized from less radiogenic melt compositions at earlier stages of magma evolution, whereas highly radiogenic biotite xenocrysts and the development of isotopic heterogeneity in matrix melt glass appear to coincide with the final stage of the evolution of the Fish Canyon magma body in the upper crust. Integrated petrographic and geochemical evidence is consistent with pre-eruptive thermal rejuvenation of a near-solidus mineral assemblage from ∼720 to 760°C (i.e. partial dissolution of feldspars + quartz while hornblende + titanite + biotite were crystallizing). Assimilation and blending of phenocrysts, antecrysts and xenocrysts reflects chamber-wide, low Reynolds number convection that occurred within the last ∼10 000 years before eruptio

    Active Response Gravity Offload and Method

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    A variable gravity field simulator can be utilized to provide three dimensional simulations for simulated gravity fields selectively ranging from Moon, Mars, and micro-gravity environments and/or other selectable gravity fields. The gravity field simulator utilizes a horizontally moveable carriage with a cable extending from a hoist. The cable can be attached to a load which experiences the effects of the simulated gravity environment. The load can be a human being or robot that makes movements that induce swinging of the cable whereby a horizontal control system reduces swinging energy. A vertical control system uses a non-linear feedback filter to remove noise from a load sensor that is in the same frequency range as signals from the load sensor

    Association of 1,5-Anhydroglucitol and 2-h Postprandial Blood Glucose in Type 2 Diabetic Patients

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    OBJECTIVE—To assess the association of 1,5-anhydroglucitol (1,5-AG) with 2-h postprandial glucose values in type 2 diabetic patients followed over 12 months in an outpatient setting

    Harmonized Landsat/Sentinel-2 Reflectance Products for Land Monitoring (Invited)

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    Many land applications require more frequent observations than can be obtained from a single 'Landsat class' sensor. Agricultural monitoring, inland water quality assessment, stand-scale phenology, and numerous other applications all require near-daily imagery at better than 1ha resolution. Thus the land science community has begun expressing a desire for a '30-meter MODIS' global monitoring capability. One cost-effective way to achieve this goal is via merging data from multiple, international observatories into a single virtual constellation. The Harmonized Landsat/Sentinel-2 (HLS) project has been working to generate a seamless surface reflectance product by combining observations from USGS/NASA Landsat-8 and ESA Sentinel-2. Harmonization in this context requires a series of radiometric and geometric transforms to create a single surface reflectance time series agnostic to sensor origin. Radiometric corrections include a common atmospheric correction using the Landsat-8 LaSRC/6S approach, a simple BRDF adjustment to constant solar and nadir view angle, and spectral bandpass adjustments to fit the Landsat-8 OLI reference. Data are then resampled to a consistent 30m UTM grid, using the Sentinel-2 global tile system. Cloud and shadow masking are also implemented. Quality assurance (QA) involves comparison of the output 30m HLS products with near-simultaneous MODIS nadir-adjusted observations. Prototoype HLS products have been processed for approximately 7% of the global land area using the NASA Earth Exchange (NEX) compute environment at NASA Ames, and can be downloaded from the HLS web site (https://hls.gsfc.nasa.gov). A wall-to-wall North America data set is being prepared for 2018. This talk will review the objectives and status of the HLS project, and illustrate applications of high-density optical time series data for agriculture and ecology. We also discuss lessons learned from HLS in the general context of implementing virtual constellations

    Impacts of dietary forage and crude protein levels on the shedding of Escherichia coli O157:H7 and Listeria in dairy cattle feces

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    Shedding of Escherichia coli O157:H7 and Listeria monocytogenes in ruminant manure is well reported. However, the influence of dietary manipulation on the shedding of the pathogens is not well understood. This study was conducted to improve the understanding of the relationship between dietary feed composition and pathogen shedding in dairy feces, particularly E. coli O157:H7 and L. monocytogenes. Twelve cows were randomly assigned to a 2 × 2 factorial arrangement of 2 dietary forage levels: low forage (37.4% of dry matter [DM]) vs. high forage (HF, 53.3% of DM) and two dietary crude protein (CP) levels: low protein (LP, 15.2% of DM) vs. high protein (HP, 18.5% of DM) in a 4 × 4 replicated Latin square design with four periods each including 15 d adaptation and 3 d sample collection. In CP treatments, significantly low concentrations of L. monocytogenes were observed from cows fed the HP (0.9-1.6 log10 cfu/g) compared to the LP diet (1.3–2.1 log10 cfu/g). Significant interaction effect was observed between dietary forage and crude protein on the presence of E. coli O157:H7 (P < 0.05) but not on L. monocytogenes. On average, the highest E. coli O157:H7 concentration (6.5 log10 cfu/g of feces) was observed from the HF and HP diet and the lowest concentration was 6.2 log10cfu/g from the HF and LP diet. The average L. monocytogenes shedding was within the range of 1.8 to 2.4 log 10cfu/g among the treatments. The study showed that diet has an influence on the shedding of pathogenic bacteria in dairy excreta
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