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Suzuki Takeshi Yoshie-Stark Yumiko Santoso Joko 《中国海洋大学学报(英文版)》2005,4(3):205-208
Seaweeds are known to hold substances of high nutritional value; they are the richest resources of minerals important to the biochemical reactions in the human body. Seaweeds also hold non-nutrient compounds like dietary fiber and polyphenols. However, there is not enough information on the mineral compounds of tropical seaweeds. Also we are interested in the antioxidant activities of seaweeds, especially those in the tropical area. In this study, Indonesian green, brown and red algae were used as experimental materials with their mineral components analyzed by using an atomic absorption spectrophotometer. The catechins and flavonoids of these seaweeds were extracted with methanol and analyzed by high performance liquid chromatography （HPLC） ; the anti-oxidant activities of these seaweeds were evaluated in a fish oil emulsion system. The mineral components of tropical seaweeds are dominated by calcium, potassium and sodium, as well as small amounts of copper, iron and zinc. A green alga usually contains epigallocatechin, gallocatechin, epigallocatechin gallate and catechin. However, catechin and its isomers are not found in some green and red algae. In the presence of a ferrous ion catalyst, all the methanol extracts from the seaweeds show significantly lower peroxide values of the emulsion than the control, and that of a green alga shows the strongest anti-oxidant extract of this alga, which is significantly different from activity. The highest chelation on ferrous ions is also found in the the other methanol extracts in both 3 and 24 h incubations. 相似文献
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Geoffrey D. Smith Robbert Wetselaar James J. Fox Robert H. M. van de Graaff Doeljachman Moeljohardjo Joko Sarwono Wiranto Sri Rahajoe Asj'ari Suharto Tjojudo Basuki 《Hydrogeology Journal》1999,7(6):576-589
The causes and nature of nitrate pollution of wells in a village within Kotagede, a subdistrict of the city of Yogyakarta,
Indonesia, were investigated in a detailed hydrological study. Nitrate concentrations in groundwater frequently exceeded the
WHO recommended limit of 50 mg L − 1. Groundwater nitrate concentrations were measured over a 19-month period in monitoring wells and in piezometers placed strategically
in relation to sewage tanks within the village. Results indicate that the tanks are major sources of nitrate in the groundwater
and that the input is markedly dependent on rainfall, resulting in a surge of nitrate into the groundwater at the beginning
of each wet season. That the tanks are a major source was confirmed by measuring nitrate in soil cores obtained by augering
close to selected tanks. Washrooms, where people wash themselves, are not significant sources of nitrate. Faecal coliform
counts in groundwater from a random selection of wells are very high. The results have implications for the siting of wells
and toilets within villages in Indonesia.
Received, January 1999/Revised, August 1999/Accepted, August 1999 相似文献
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A comparison between commonly used techniques for hydrograph recession analysis, namely the semi‐logarithmic plot of a single recession segment, the master recession and a relatively new approach based on wavelet transform was carried out. These methods were applied to a number of flood hydrograph events of two catchments in West Java, Indonesia. The results show that all the methods tested produce reasonable and comparable results. However, problems arise in the semi‐logarithmic plot and the master recession, i.e. determining the recession parameter K is not an easy task especially where the plotted data on a semi‐logarithmic plot is not a linear but a curved line. On a curved line, the end of direct flow or starting point of baseflow is not clear and it is quite difficult to identify. Hence, the best line as a basis for computing the recession parameter K becomes uncertain. The wavelet transform approach, however, produces promising results and minimizes a number of problems associated with hydrograph recession analysis. The end of direct flow and the location of the baseflow component are easily determined through the wavelet maps. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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Relevance of peat draining rivers in central Sumatra for the riverine input of dissolved organic carbon into the ocean 总被引：1，自引：0，他引：1
Sources and discharges of dissolved organic carbon (DOC) from the central Sumatran river Siak were studied. DOC concentrations in the Siak ranged between 560 and 2594 μmol l−1 and peak out after its confluence with the river Mandau. The Mandau drains part of the central Sumatran peatlands and can be characterized as a typical blackwater river due to its high DOC concentration, its dark brown-coloured, acidic water (pH 4.4–4.7) and its low concentration of total suspended matter (12–41 mg l−1). The Mandau supplies about half of the DOC that enters the Siak Estuary where it mixes conservatively with ocean water. The DOC input from the Siak into the ocean was estimated to be 0.3 Tg C yr−1. Extrapolated to entire Indonesia the data suggest a total Indonesian DOC export of 21 Tg yr−1 representing 10% of the global riverine DOC input into the ocean. 相似文献
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