Protein digestibility-corrected amino acid scores for bean and bean-rice infant weaning food products     

Kannan S  Nielsen SS  Mason AC 《Journal of agricultural and food chemistry》2001,49(10):5070-5074

Vegetable proteins are an integral part of infant weaning diets in Latin America. Protein quality in plant-based products, however, is constrained by amino acid composition and intrinsically present antinutritional factors. The goal of this study was to improve bean protein quality by utilizing fermentation and germination processing. The objectives were to determine if protein quality, as measured by Food and Agricultural Organization (FAO) approved True Protein Digestibility (TPD) and Protein Digestibility-Corrected Amino Acid Scores (PDCAAS), of formulated bean-based weaning products could be improved upon fermentation and germination and if protein quality could be further improved when processed beans were combined with cooked rice. Results showed that the highest TPD and PDCAAS values were obtained for cooked germinated beans combined with rice. The TPD values for products ranged from 80 to 91%, and the PDCAAS values were 0.38-0.51. There was no significant increase (P < 0.05) of either TPD or PDCAAS values upon fermentation. Germination increased TPD of cooked bean products; this increase was not, however, accompanied by an increase in PDCAAS. When combined with rice, the PDCAAS values for all bean products improved significantly, thus supporting the concept of cereal-legume complementation. In conclusion, this study showed the range of PDCAAS in processed black bean and bean-rice infant weaning food products. The potential for incorporation of these products into the diets of weaning age Latin American children would, however, be confirmed only after validation with growth or metabolic balance studies in human infants.  相似文献   

Mercury speciation in open ocean waters     

R. P. Mason  W. F. Fitzgerald 《Water, air, and soil pollution》1991,56(1):779-789

Vital to our understanding of the biogeochemical cycling of Hg and the origin of the enhanced monomethylmercury (MMHg) concentrations in biota is knowledge of the sources, behavior and fate of methylated Hg species in natural waters. Methylated Hg species, dissolved gaseous and reactive mercury were measured in the equatorial Pacific Ocean in early 1990. Both dimethylmercury (DMHg) and MMHg were found in the subthermocline waters of the equatorial Pacific Ocean. Maxima in alkylmercury species in the O₂ minimum region coincided with a decrease in reactive mercury. A significant inverse correlation between DMHg, and MMHg, concentration and O₂ content was observed. A maximum in reactive mercury was observed in the region of the thermocline, with similar concentrations in the surface and deeper waters. Atmospheric deposition is not a significant source of MMHg to this region. The data suggest formation of alkylmercury species in the low oxygen zone, with Hg(II) being the most likely substrate. A model for the cycling of Hg species in the equatorial Pacific Ocean is presented. These results are the first direct evidence of a significant open ocean source of methylated Hg species and suggest a pathway for mercury accumulation in pelagic fish.  相似文献   

Sedimentary aggregates in the Peoria Loess of Nebraska, USA     

Joseph A. Mason  Peter M. Jacobs  Richard S. B. Greene  W. D. Nettleton 《CATENA》2003,53(4):574

Loess grain size data used to infer transport direction or wind strength are generally derived from vigorously disaggregated samples. However, these data may not adequately represent the effective particle size distribution during loess transport, if the transported dust contained aggregates of fine-grained material. Thin sections of minimally altered C and BC horizons in the late Pleistocene Peoria Loess of Nebraska, USA, indicate the presence of aggregates with diameters of 30–1000 μm. The larger aggregates (>250 μm) are unlikely to have been transported, and are interpreted as the result of soil faunal activity and other pedogenic processes after deposition. Aggregates smaller than 250 μm could have a similar origin, but laser diffraction particle size analysis suggests that many are sedimentary particles. Comparison of minimally and fully dispersed particle size distributions from each sampling site was used to estimate the modal diameter of aggregates. The aggregate modal diameter becomes finer with decreasing loess thickness, representing increasing distance from the source. A similar trend was observed in the modal diameter of fully dispersed particle size distributions, which represents the mode of sand and silt transported as individual grains. We interpret both trends as the result of sorting during transport, supporting the interpretation that many of the aggregates were transported rather than formed in place. Aggregate content appears to increase with distance from the source, explaining a much more rapid downwind increase in clay content than would be expected if clay were transported as particles smaller than 2 μm diameter. Although the Peoria Loess of Nebraska contains sedimentary aggregates, many of the coarse silt and sand grains in this loess were transported as primary particles, were thoroughly exposed to sunlight and are potentially well suited for luminescence dating.  相似文献   

Onondaga Lake and the dynamics of chloride in the Oswego River     

Steven W. Effler  Mary Gail Perkins  Stephen D. Field 《Water, air, and soil pollution》1984,23(1):69-80

The temporal distribution of chloride concentration in the Oswego River was determined at 6 hr intervals for a 3 mo period during the summer of 1982. The dynamics of relative flow and chloride contributions from the three major sources forming the Oswego River, and the dynamics of flow releases from one of the sources, chloride-polluted Onondaga Lake, were determined from the above measurements, available chloride concentrations, and flow data for the system, through application of a simple mass balance on chloride. The chloride concentration and load in the Oswego River were found to be highly variable with time, and largely due to the dynamics of flow release from Onondaga Lake. The chloride distribution in the Oswego River, with its unique dynamics and chemically conservative nature, make it a valuable hydraulic tracer for the system.  相似文献   

Phosphorus management strategies for lakes: Edited by R. C. Loehr,C. S. Martin and W. Rast. Ann Arbor Science,Ann Arbor,Michigan. 1980. 490 pp. 23 × 15 cm. ISBN 0 250 40332 3. Price: £23·10     

C.F. Mason 《Biological conservation》1982,22(2):165-166

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Compositional changes of Australia-grown Western Schley pecans [Carya illinoinensis (Wangenh.) K. Koch] during maturation     

Singanusong R  Mason RL  D'Arcy BR  Nottingham SM 《Journal of agricultural and food chemistry》2003,51(2):406-412

Changes in composition during the maturation of Western Schley pecans [Carya illinoinensis(Wangenh.) K. Koch] grown in Australia were investigated. Pecans of different maturity levels were collected at monthly intervals between March and June in 1999 and 2000 and analyzed for the concentrations of moisture, total lipid, sucrose, raffinose, protein, and the minerals aluminum, boron, calcium, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, sulfur, and zinc. Moisture, total lipid, and calcium contents changed significantly (p < 0.05) with harvest time and maturity, whereas the other components did not. Western Schley pecans grown in Australia should be harvested after the shuck has opened and it is either green or brown in color to maximize total lipid content and quality. This occurred after May 11 in 1999 and after May 17 in 2000.  相似文献   

Acidification and other (Lutra lutra) distribution in Scotland     

C. F. Mason  S. M. MacDonald 《Water, air, and soil pollution》1989,43(3-4):365-374

The influence of acidification on otters (Lutra lutra) was assessed in three regions of Scotland. A total of 72 stretches of 1000 m of riverbank were searched for all signs of otters on three occasions. Water chemistry was determined and habitat was assessed for its suitability to otters. A further series of water samples were collected after a period of very heavy rain in midwinter; conductivity and pH were measured and total Al was determined on a filtered, acidified sample. Otters were recorded at all sites. There were highly significant correlations between use by otters of stretches (measured in terms of marking intensity) and both pH and conductivity, with pH accounting for the greatest proportion of variation in otter signs in a stepwise multiple regression. The relation between otter signs and water quality was greatest in Galloway, the region with significantly more acid waters. There were significantly fewer signs of otters in stretches with minimum pH thought to be detrimental to fish populations for two regions, Galloway and Sutherland.  相似文献   

The oxygen resources of the hypolimnion of ionically enriched onondaga lake,NY, U.S.A.     

Steven W. Effler  Mary Gail Perkins  Carol Brooks 《Water, air, and soil pollution》1986,29(1):93-108

The depletion of hypolimnetic DO and the upper depth boundary of anoxia for four different years (1978, 1979, 1980 and 1981), and the accumulation of sulfide for a single year (1981), are documented for ionically enriched hypereutrophic Onondaga Lake, NY, USA. The depletion rate, represented as the areal hypolimnetic oxygen deficit (AHOD, g m^?2 day^?1), was extremely high (1.2–2.7 g m^?2 day^?1), The large differences in the rate within individual years and from year to year were largely a result of differences in attendant vertical mixing (parameterized as the hypolimnetic heating rate). The entire hypolimnion (depth interval from 11 to 20 m) was without O₂ by late June of all 4 yr; anoxia was observed above the hypolimnion on some occasions when secondary stratification occurred. Sulfide accumulated progressively in the hypolimnion in 1981 following the onset of anoxia to a volume weighted concentration of I1 mg L^?1. The ionic discharge from an adjoining alkali manufacturer exacerbated the problem of limited O₂ resources of the hypolimnion by: (1) decreasing vertical mixing, (2) prolonging the duration of stratification, (3) causing abbreviated turnovers, and (4) encouraging increased rates of phytoplankton settling.  相似文献   

Radioactivity in otter scats in Britain following the chernobyl reactor accident     

C. F. Mason  S. M. Macdonald 《Water, air, and soil pollution》1988,37(1-2):131-137

Radioactivity was determined in samples of otter (Lutra lutra) faeces (scats) collected from various regions of Great Britain in 1986 and 1987, following the Chernobyl nuclear reactor accident, and compared with a sample of scats collected in 1985 from central Wales. Samples of scats were also collected from the seashore adjacent to the Dounreay nuclear power station, northern Scotland, and compared with a control site, 40 to 60 km distant. Samples collected in 1986 from central Wales, Galloway and northern Scotland all contained significantly higher amounts of radioactivity than the 1985 sample from central Wales, with Galloway (mean 13 000 Bq kg^?1 dry weight) having significantly more radioactivity than other regions. A sample collected in central Wales in January 1987 had returned to the 1985 level of radioactivity, but a sample from Galloway in January 1987 remained high; this difference in response may be related to the acidic nature of Galloway rivers. No significant differences were found between samples collected from near Dounreay and the control site, though fallout from Chernobyl may have masked the effects of local discharges of radioactivity. The significance of the results to otter populations is discussed.  相似文献   

Enhanced bioremediation of soil containing 2,4-dinitrotoluene by a genetically modified Sinorhizobium meliloti     

Sisir K Dutta  Gail P HollowellFawzy M Hashem  L David Kuykendall 《Soil biology & biochemistry》2003,35(5):667-675

The symbiotic nitrogen-fixing soil bacterium, Sinorhizobium meliloti, is well known for its ability to interact with the leguminous plant Medicago sativa L. It has, however, not been reported that this species possesses the capability to degrade toxic nitroaromatic compounds, such as 2,4-dinitrotoluene (DNT) which is commonly associated with the degradation of the explosive trinitrotoluene (TNT). In this study, the pJS1 DNT-biodegradative plasmid was genetically transferred to S. meliloti strain USDA 1936, which was confirmed by plasmid profile analysis. Several standard analytical and chemical tests including high performance liquid chromatography (HPLC), nitrite (NO₂) release assays, rhizosphere population and plant greenhouse studies were conducted to test the ability of S. meliloti to degrade 2,4-DNT. The possible presence of 2,4-DNT remaining in the treated soil was tested, and no 2,4-DNT had been absorbed by the soil. The pJS1-carrying recombinant strain DHK1 produced ‘ARC’ alfalfa plants that were almost 2-fold higher in shoot dry weight than that produced by the parent strain on soil containing 0.14 mM 2,4-DNT. The transconjugant strain DHK1 reduced significantly one-third more 2,4-DNT in both 0.14 and 0.28 mM contaminated soil, and in 0.55 mM contaminated soil it degraded 94% of the 2,4-DNT present. In liquid cultures, however, only about 4% reduction in 2,4-DNT concentrations was obtained in 10 days. We interpret the results as clearly establishing that genetic modification was successfully used, for the first time, to improve the capability of the symbiotic nitrogen-fixing soil bacterium S. meliloti DHK1 to bioremediate in situ 2,4-DNT-contaminated soil in the presence of alfalfa plants.  相似文献