2,797 research outputs found

    Euler-like modelling of dense granular flows: application to a rotating drum

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    General conservation equations are derived for 2D dense granular flows from the Euler equation within the Boussinesq approximation. In steady flows, the 2D fields of granular temperature, vorticity and stream function are shown to be encoded in two scalar functions only. We checked such prediction on steady surface flows in a rotating drum simulated through the Non-Smooth Contact Dynamics method. This result is non trivial because granular flows are dissipative and therefore not necessarily compatible with Euler equation. Finally, we briefly discuss some possible ways to predict theoretically these two functions using statistical mechanics

    Lesser in vitro anaerobic cecal isoflavone disappearance was associated with greater apparent absorption of daidzein and genistein in Golden Syrian hamsters

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    Our hypothesis in this study was that in vitro disappearance of isoflavones from fecal or cecal contents of Golden Syrian hamsters paralleled the apparent absorption of these compounds, comparable with previous findings from in vitro human fecal incubations. Two studies were conducted to test this idea: one on in vitro fecal (study 1, n = 20/sex) and the other on in vitrocecal contents (study 2, n = 10/sex) ability to degrade isoflavones. According to HPLC analysis, urinary isoflavone excretion was significantly less by 2–4 fold in males compared with females in both studies. Fecal isoflavone excretion was not significantly different between sexes orisoflavones (study 1) and was In vitro anaerobic fecal isoflavonedegradation rate constants from study 1 were minimal with no significant correlation between urinary and fecal isoflavone excretion. However, in vitro anaerobic cecal isoflavone degradation rate constants (study 2) were greater and significantly correlated with urinary excretion ofdaidzein (R = 0.90; p = 0.01) and genistein (R = 0.93; p = 0.004), but not glycitein (R = 0.50; p = 0.3). Both male and female hamsters showed a pattern of urinary isoflavone excretion similar to that found in humans (daidzein \u3e genistein). Hamster in vitro cecal isoflavone degradation rate constants seemed to be analogous to human in vitro fecal isoflavone degradation rate constants for genistein and daidzein. The sex difference in isoflavone excretion in hamsters and the instability in glycitein excretion across studies coupled with the paucity of human data on thisisoflavone deserve further investigation

    Americans’ Global Warming Beliefs and Attitudes

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    This report presents results from a national study of what Americans understand about how the climate system works, and the causes, impacts, and potential solutions to global warming. Among other findings, the study identifies a number of important gaps in public knowledge and common misconceptions about climate change. Educational levels: Graduate or professional, Undergraduate upper division, Undergraduate lower division, General public

    The S shape of a granular pile in a rotating drum

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    The shape of a granular pile in a rotating drum is investigated. Using Discrete Elements Method (DEM) simulations we show that the "S shape" obtained for high rotation speed can be accounted for by the friction on the end plates. A theoretical model which accounts for the effect of the end plates is presented and the equation of the shape of the free surface is derived. The model reveals a dimensionless number which quantifies the influence of the end plates on the shape of the pile. Finally, the scaling laws of the system are discussed and numerical results support our conclusions

    Changes in Grape Maturity Induced by Spraying Ethanol

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    Three different ethanol solutions were sprayed onto Cabernet Sauvignon (Vitis vinifera L.) clusters during the ripening period: 2.5, 5 and 10% by volume in water. Controls were sprayed with water alone. Three different times of spraying were also tested: 8, 10 and 13 weeks post-flowering. One of the observed changes was a lower titratable acidity in grape samples at harvest, when the clusters were sprayed with ethanol at 10 weeks, in comparison with controls. The wines made with grapes treated with ethanol after mid-veraison, had higher ODs at 520 nm than did the controls. This may due to a combined effect of red pigment levels and acidity. In addition, following malolactic fermentation, the acidity levels of wines made with ethanoltreated grapes were slightly higher than those made with the control grapes. Spraying ethanol at 13 weeks post-flowering increased the berry weight by 10% at harvest without decreasing the °Brix value. The corresponding wines had similar degrees of alcohol. This observation was made for the first time in 2001

    Metabolism of Glycitein (7,4-Dihydroxy-6-methoxy-isoflavone) by Human Gut Microflora

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    Gut microbial disappearance and metabolism of the soy isoflavone glycitein, 7,4‘-dihydroxy-6-methoxyisoflavone, were investigated by incubating glycitein anaerobically with feces from 12 human subjects. The subjects\u27 ages ranged from 24 to 53 years with a body mass index (BMI) of 20.9−25.8 kg/m2 (mean BMI = 24.0 ± 1.1 kg/m2). Glycitein disappearance followed an apparent first-order rate loss. Fecal glycitein disappearance rates for the subjects segregated into three different groups described as high (k = 0.67 ± 0.14/h), moderate (k = 0.34 ± 0.04/h), and low (k = 0.15 ± 0.07/h) glycitein degraders (p \u3c 0.0001). There was no dose effect on the disappearance rates for each subject from 10 to 250 μM glycitein (averagek = 0.32 ± 0.03/h, p \u3e 0.05). Four putative glycitein metabolites, characterized by liquid chromatography−mass spectrometry (electrospray ionization using positive ionization mode), were dihydroglycitein, dihydro-6,7,4‘-trihydroxyisoflavone, and 5‘-O-methyl-O-desmethylangolensin. Two subjects produced a metabolite tentatively identified as 6-O-methyl-equol, and one subject produced daidzein as an additional metabolite of glycitein. These results show that glycitein is metabolized by human gut microorganisms and may follow metabolic pathways similar to other soy isoflavones

    Greater Apparent Absorption of Flavonoids Is Associated with Lesser Human Fecal Flavonoid Disappearance Rates

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    -OH-flavonoids disappeared more rapidly from human fecal incuba- tions and were less absorbable by humans than flavonoids without 5-OH moieties. Anaerobic fecal disappearance rates over 24 h were determined for 15 flavonoids in samples from 20 men and 13 women. In these anaerobic fecal mixtures, flavonoids with 5,7,40-OH groups, genistein, apigenin, naringenin, luteolin, kaempferol, and quercetin (disappearance rate, k = 0.46 ( 0.10 h-1), and methoxylated flavonoids, hesperetin and glycitein (k = 0.24 ( 0.21 h-1), disappeared rapidly compared with flavonoids lacking 5-OH (e.g., daidzein, k = 0.07 ( 0.03 h-1). Apparent absorption of flavonoids that disappeared rapidly from in vitro fecal incubations, genistein, naringenin, quercetin, and hesperetin, was compared with that of daidzein, a slowly disappearing flavonoid, in 5 men and 5 women. Subjects ingested 104 μmol of genistein and 62 μmol of daidzein (soy milk), 1549 μmol of naringenin and 26 μmol of hesperetin (grapefruit juice), and 381 μmol of quercetin (onions) in three test meals, each separated by 1 week. Blood and urine samples were collected over 24 h after each test meal. Plasma flavonoid concentrations ranged from 0.01 to 1 μM. The apparent absorption, expressed as percentage of ingested dose excreted in urine, was significantly less for naringenin (3.2 ( 1.7%), genistein (7.2 ( 4.6%), hesperetin (7.3 ( 3.2%), and quercetin (5.6 ( 3.7%) compared with daidzein (43.4 ( 15.5%, p = 0.02). These data affirmed the hypothesis that the 5,7,40-OH of flavonoids limited apparent absorption of these compounds in humans

    A metabolism perspective on alternative urban water servicing options using water mass balance

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    Urban areas will need to pursue new water servicing options to ensure local supply security. Decisions about how best to employ them are not straightforward due to multiple considerations and the potential for problem shifting among them. We hypothesise that urban water metabolism evaluation based a water mass balance can help address this, and explore the utility of this perspective and the new insights it provides about water servicing options. Using a water mass balance evaluation framework, which considers direct urban water flows (both ‘natural’ hydrological and ‘anthropogenic’ flows), as well as water-related energy, we evaluated how the use of alternative water sources (stormwater/rainwater harvesting, wastewater/greywater recycling) at different scales influences the ‘local water metabolism’ of a case study urban development. New indicators were devised to represent the water-related ‘resource efficiency’ and ‘hydrological performance’ of the urban area. The new insights gained were the extent to which alternative water supplies influence the water efficiency and hydrological performance of the urban area, and the potential energy trade-offs. The novel contribution is the development of new indicators of urban water resource performance that bring together considerations of both the ‘anthropogenic’ and ‘natural’ water cycles, and the interactions between them. These are used for the first time to test alternative water servicing scenarios, and to provide a new perspective to complement broader sustainability assessments of urban water

    Human Gut Microbial Degradation of Flavonoids:  Structure−Function Relationships

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    The relationship between chemical structure and gut microbial degradation rates of 14 flavonoids, flavone, apigenin, chrysin, naringenin, kaempferol, genistein, daidzein, daidzin, puerarin, 7,4‘-dihydroxyflavone, 6,4‘-dihydroxyflavone, 5,4‘-dihydroxyflavone, 5,3‘-dihydroxyflavone, and 4‘-hydroxyflavone, was investigated by anaerobically fermenting the flavonoids with human gut microflora (n = 11 subjects). Degradation rates for the 5,7,4‘-trihydroxyl flavonoids, apigenin, genistein, naringenin, and kaempferol, were significantly faster than the other structural motifs. Puerarin was resistant to degradation by the gut microflora. Extensive degradation of flavonoids by gut microflora may result in lower overall bioavailability than those flavonoids that are slowly degraded because rapidly degrading flavonoids are less likely to be absorbed intact
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