974 resultados para nickel, cobalt and copper determination
Resumo:
Most of the gemcitabine (dFdC) resistant cell lines manifested high NF?B activity. The NF?B activity can be induced by dFdC and 5-FU exposure. The chemosensitizing effect of disulfiram (DS), an anti-alcoholism drug and NF?B inhibitor, and copper (Cu) on the chemoresistant cell lines was examined. The DS/Cu complex significantly enhanced the cytotoxicity of dFdC (resistant cells: 12.2–1085-fold) and completely reversed the dFdC resistance in the resitant cell lines. The dFdC-induced NF?B activity was markedly inhibited by DS/Cu complex. The data from this study indicated that DS may be used in clinic to improve the therapeutic effect of dFdC in breast and colon cancer patients.
Resumo:
Deep sea manganese nodules are considered as important natural resources for the future because of their Ni, Cu and Co contents. Their different shapes cannot be correlated clearly with their chemical composition. Surface constitution, however, can be associated with the metal contents. A classification of the nodules is suggested on the basis of these results. The iron content of the nodules strikingly shows relations to the physical properties (e.g. density and porosity). The method of density-measurement is the reason for this covariance. The investigation of freeze-dried nodular substance does not give this result. The Fe-rich nodules lose more hydration water than the Fe-poor ones during heat drying. The reason for this effect is the different crystallinity, respectively the particle size. The mean particle size is calculated on the basis of geometrical models. The X-ray-diffraction analysis proves the variation of crystallinity in connection with the Fe-content, too. The internal nodular textures also show characteristic distinctions.
Resumo:
Data comes from the NGDC database, https://www.ngdc.noaa.gov/.
Resumo:
Petrological, mineralogical and chemical investigations of marine manganese nodules from the West Pacific revealed the intimate relation between the chemical and mineral compositions and the remarkable preferential partitioning of metal elements in the ferromanganese minerals. The microscopic observations of textures of manganese nodules tell the growth history of manganese nodules and the formation conditions of ferromanganese minerals. Chemical compositions of nodules from Komahashi-Daini Seamount are very similar to those of the nodules from marginal banks and seamounts. Compositional variations in the bulk composition of nodules collected from the same dredge haul are considerably small, suggesting the similarity of the growth history of individual nodules, although the contents of metal elements vary remarkably from layer to layer in a single nodule.
Resumo:
Chemical analyses of manganese nodules from the Central Pacific Basin show that their chemical composition varies regionally, although that of the associated sediments is markedly uniform throughout the basin. Mn content varies from 16 to 32% in average. Its higher value is generally found in nodules from siliceous clay and a few from deep-sea clay. Fe content tends to enrich in nodules from deep-sea clay area. Most manganese nodules, except those from deep-sea clay, are remarkably depleted in Fe compared with ones from the other Pacific regions. Mostly, Cu and Ni contents exceed 1% in nodules from siliceous clay, and decrease towards the northwest of the basin where deep-sea clay is distributed. The inter-element relationship between manganese nodules and associated sediments suggests that the mechanism of incorporation of major and minor elements in nodules is apparently different from that of the associated sediments. This finding seems to provide a new interpretation on the problem why manganese nodules having low accumulation rate are not buried by the associated sediments with greater sedimentation rate and then occur on sediment-seawater interface.
Resumo:
The major and some of the minor constituents and the rate of accumulation of manganese nodules in the western North Pacific were determined. Manganese concentration in the nodules ranged from 20 to 30 per cent in the acid soluble fraction. As to the rare earth concentration, enrichment of cerium was observed in the manganese nodule as compared with that in shales or sea water. Thorium to uranium ratio in the nodule ranged from 9.4 to 14.3, which was very much higher than that in sea water. From the distribution of excess ionium, excess protactinium and Io/Th ratio, a rate of accumulation of 7 mm per million years was obtained with the surface layer of several mm in thickness of the JEDS-4-E4 nodule.
Resumo:
Ferromanganese concretions from ten stations in the Barents Sea have been analysed for 24 elements. The deposits occur as discoidal and flat concretions and as coatings, in the latter case on lithified or detrital material or as extensive pavements on the Svalbard shelf. The concretions are compositionally similar to Baltic concretions but differ considerably from deep-ocean nodules, particularly in Cu, Ni and Co contents. Statistical analyses reveal distinct correlations between Mn, Na, Ba, Ni and Cu; the Mn-rich coatings showed enrichment of Mo, Zn and possibly Co in a Mn-phase. The iron phase holds high concretions of P and As. Two iron-rich concretions with high contents of P, Ca, Sr, Y, Yb and La were found east and northeast of Spitsbergen Banken, probably indicating upwelling of nutrient-rich, cold polar water along the Svalbard shelf.
Resumo:
The trace element content of different bog ores has been measured and it appeared that most of these elements are enriched in the manganiferous bog ores as compared with the ferriferous ones. The manganiferous bog ores have also proved to have a higher radioactivity than the ferriferous ones.
Resumo:
During Cruise VA 04/2 of the R. V. Valdivia in 1972, numerous samples were collected of manganese nodules, sodiments, and the pore water of the Sediments in the area betwoen 6° N and 11° N and between 149° W and 154° W in the Central Pacific. This paper reports on the geochemical study of 70 manganese nodules from 12 stations (box-core and dredge samples). The nodules Irom a single Station vary considerably in diemical composition. These variations are of the same magnitude as the variations in nodule composition over the entire survey area. The ratios of manganese to nickel, copper, and zinc show good positive correlation as do the ratios of iron to lead and, to a lesser extent, of iron to cobalt. No correlation was found between the environment of the manganese nodules and their metal content. Three internal zones, the outer. intermediate, and core zones, of some nodules were studied in detail. Trends of differences of Chemical composition from surface to core were found for numerous elements and elemental ratios.
Resumo:
Sea floor dredging by the H.M.S. Challenger, the U.S.S. Albatross, the U.S.S. EPC(R) 857, and vessels of the Scripps Institution of Oceanography shows that extensive deposits of manganese nodules are on the deep sea floor and that crusts of manganese dioxide cover many seamounts. Sea floor photography reveals that in some places these crusts are quite continuous and the nodules are closely packed. These crusts and nodules are fully oxidized and hydrated mixtures of man¬ganese and iron plus earthy impurities. Also, relatively high concen¬trations of the trace elements nickel, copper, and cobalt are present.