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  • 2020-2022
  • 1985-1989  (61)
  • 1960-1964  (11)
  • 1920-1924
  • Phosphorus
  • Polymerization
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 29 (1989), S. 367-369 
    ISSN: 1432-1432
    Keywords: Guanosine derivatives ; Self-aggregation ; Amino acids ; Polymerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The adduct IIa, in which glycine is linked to the 3′-amino group of 3′-amino-3′-deoxyguanosine-5′-phosphate, condenses very efficientlyin aqueous solution when treated with a watersoluble carbodiimide to give long oligomeric products. The corresponding cytidine derivative IIb yields a complex mixture of very short oligomers. We believe that the efficient condensation reaction occurs in a hydrogen-bonded tetrahelical aggregate of a type that is known to form with many guanosine derivatives.
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  • 2
    ISSN: 1432-1939
    Keywords: Allocation ; Growth ; Phosphorus ; Photosynthesis ; Seed size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Under favorable nutrition, accessions of the weedy barleygrass (Hordeum leporinum and H. glaucum) had a higher relative growth rate (RGR) than did accessions of cultivated barley (H. vulgare) or its wild progenitor (H. spontaneum). RGR was not positively correlated with the presumed level of soil fertility at the collection site of an accession either within or among species. RGR was reduced more strongly by low-P supply in the progenitor than in the crop or weed, indicating that selection of cultivars to grow in fertile soils had not reduced their potential to grow effectively under low-P conditions. Seed and embryo masses were more important than RGR in determining plant size. Relative differences among assessions in plant size declined with time, because (1) accessions with small seeds had a higher RGR, and (2) RGR of large-seeded accessions declined with time. Absolute growth rate correlated positively with leaf area and negatively with photosynthetic rate per unit leaf area. Under favorable nutrition, maximum photosynthetic rate correlated negatively with leaf length and therefore was higher in the weeds than in the crop or progenitor accessions. P absorption potential did not differ consistently among species but generally increased in response to P stress. Cultivars produced a few tall tillers, whereas weeds and progenitors produced many small tillers. The cultivar had a larger proportion of reproductive tillers, allocated a larger proportion of biomass to grain, and produced larger grains than did the weedy accession. By contrast, the weed began maturing seeds sooner, produced more reproductive tillers, and produced more grains per car and per plant than did the cultivar. The study suggests two major conclusions: (1) A low RGR is not an adaptation to low P supply in annual Hordeum species. (2) Seed size is the major determinant of early plant size between accessions in these Hordeum species under favorable nutrition. However, large seed size indirectly results in a low RGR because of the inverse relationship between plant size and RGR and results in a low photosynthetic rate because of the inverse relationship between leaf size and photosynthesis.
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  • 3
    ISSN: 1432-1939
    Keywords: Panolis flammea ; Pinus ; Nitrogen ; Phosphorus ; Tannins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This paper reports part of a study to determine why damaging outbreaks of the pine beauty moth, Panolis flammea (D & S) (Lepidoptera: Noctuidae), in Scotland are frequent on lodgepole pine but do not occur on Scots pine, and why outbreaks on lodgepole pine are mainly confined to trees growing in deep unflushed peat. The elongation of shoots and the growth of needles of Scots pine occurred later in the season than did those of lodgepole pine. The foliage of Scots pine generally had a higher level of nitrogen, and consistently had a higher level of phosporus, but had a consistently lower level of tannins than that of lodgepole pine during the period when the larvae were feeding each year. The nitrogen content of the foliage of lodgepole pine growing in an iron pan soil was generally higher than that of lodgepole pine growing in deep peat during the same period but there were no general differences in the phosphorus or tannin contents of lodgepole pine in the 2 soil types. These findings suggest that Scots pine is a more suitable host plant than lodgepole pine and that the foliage of lodgepole pine growing in deep peat is not more suitable than lodgepole pine growing in an iron pan soil. On the basis of the chemical analyses used in this study, it is concluded that the abundance of pine beauty moth in Scotland is not strongly influenced by the nutritional suitability of its host plants.
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  • 4
    ISSN: 1432-1009
    Keywords: Acid precipitation ; Biomass nutrients ; Calcium ; Clearcutting ; Magnesium ; Nitrogen ; Phosphorus ; Potassium ; Soil leaching ; Soil nutrients ; Timber harvest ; Weathering ; Whole-tree harvest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Both harvest removal and leaching losses can deplete nutrient capital in forests, but their combined long-term effects have not been assessed previously. We estimated changes in total soil and biomass N, Ca, K, Mg, and P over 120 years from published data for a spruce-fir site in Maine, two northern hardwood sites in New Hampshire, central hardwood sites in Connecticut and Tennessee, and a loblolly pine site in Tennessee. For N, atmospheric inputs counterbalance the outputs, and there is little long-term change on most sites. For K, Mg, and P, the total pool may decrease by 2%–10% in 120 years depending on site and harvest intensity. For Ca, net leaching loss is 4–16 kg/ha/yr in mature forests, and whole-tree harvest removes 200–1100 kg/ha. Such leaching loss and harvest removal could reduce total soil and biomass Ca by 20%–60% in only 120 years. We estimated unmeasured Ca inputs from rock breakdown, root-zone deepening, and dry deposition; these should not be expected to make up the Ca deficit. Acid precipitation may be the cause of current high leaching of Ca. Although Ca deficiency does not generally occur now in acid forest soils, it seems likely if anthropogenic leaching and intensive harvest removal continue.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Aquatic sciences 51 (1989), S. 181-191 
    ISSN: 1420-9055
    Keywords: Phosphorus ; sedimentation ; Lake Constance ; particles ; calcite POM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Despite decreasing nutrient loading of Lake Constance over the past few years, annual sedimentation rates of dry matter remained nearly constant at a level of about 1000 gm−2y−1. The phosphorus content in settling material varied between 0.13 and 0.22% of dry weight. Phosphorus was transported to the lake bottom mainly by POM and by coprecipitation with authigenically formed calcite (estimated from results of laboratory studies). Adsorption to sinking particles of allochthonous origin was of minor importance. The effect of a self-cleaning mechanism is discussed with regard to continuously declining contents of dissolved phosphorus in Lake Constance since 1981, due to external sanitation measures in the drainage area.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Aquatic sciences 51 (1989), S. 192-210 
    ISSN: 1420-9055
    Keywords: Phosphorus ; mass-balance models ; sedimentation ; error propagation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The empirical adequacy of four phosphorus mass-balance models is evaluated with respect to how the prediction error variance of the corresponding net sedimentation parameters is propagated in the steadystate equations. Using the criterion of minimum propagation error variance (PEV), different groups of lakes can be distinguished for which different empirical equations are used to predict net phosphorus sedimentation. The classification reduced prediction error significantly and also reflected different patterns of sedimentation. Application of this criterion to time-series of individual lakes shows that it is possible to determine a priori whether net annual sedimentation will be better correlated to the annual loading or to the lake content. The correlations depended also on the load/lake content ratio, suggesting that net sedimentation is best viewed as the sum of the partial sedimentation of the load and of the partial sedimentation of the lake content. On average, 25% of the load and 18% of the lake content are sedimented annually. Viewing net phosphorus sedimentation as a function of both the load and the lake content can also explain and predict the well-known cross-sectional correlation between phosphorus retention and water residence time.
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  • 7
    ISSN: 1573-4943
    Keywords: Polymerization ; carboxylate reactivity ; isopeptide bond ; erythrocyte sickling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Carboxyl groups of HbS are readily activated by water-soluble carbodiimide atpH 6.0 and room temperature. These o-acylurea intermediates (activated carboxyl) are accessible for nucleophilic attack by amines. With glycine ethyl ester, the amidation is very selective for the γ-carboxyl of Glu-43(β) and more than 65% of the glycine ethyl ester incorporated is on this carboxyl group. In contrast, glucosamine derivatizes the γ-carboxyl group of Glu-22(β) as well as that of Glu-43(β) to nearly the same degree. However, the total amidation of HbS by glucosamine is lower than that with glycine ethyl ester. The differential selectivity of the two amines is apparently related to the differences in the microenvironment of the γ-carboxyl groups of Glu-22(β) and Glu-43(β), which either facilitates or refracts the aminolysis of the activated carboxyl with the two amines to different degrees. The carboxyl groups of isolated β-chain exhibit a higher reactivity for amidation with glycine ethyl ester than does the tetramer. The carboxyl groups of Glu-22(β) and Glu-43(β) and that of Asp-47(β) are all activated by carbodiimide suggesting that the higherpKa of these carboxyl groups (facilitating the activation) is a property of tertiary interaction of the polypeptide chain. The interaction of the β-chain with α-chain, i.e., generation of the quaternary interactions, reduces overall reactivity of the carboxyl groups of the protein. The higher selectivity of hemoglobin S for amidation at Glu-43(β) with glycine ethyl ester compared with that of isolated β-chain appears to be primarily a consequence of decreased amidation at sites other than at Glu-43(β).
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  • 8
    ISSN: 1573-0867
    Keywords: Phosphorus ; lupin ; chickpea ; wheat ; nodulation ; dry matter production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A glasshouse experiment was conducted to examine the comparative growth and P uptake response following P fertilizer application in lupins (Lupinus angustifolius L. cv. Chittick) and chickpeas (Cicer arietinum cv. Tyson) compared to wheat (Triticum aestivum cv. Sunstar). Measurements of dry matter, phosphorus uptake and nodule numbers were made at 50 and 100 days after sowing. At the 50 day harvest, the two legume crops produced less dry matter and accumulated less plant P than wheat but no such species interactions were present at the 100 day harvest. Chickpeas showed strong positive responses in nodule numbers with increasing rates of P fertilizer while such effects were less and more variable with lupins.
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  • 9
    ISSN: 1432-0878
    Keywords: Mantle dentin matrix ; Electron spectroscopic imaging (ESI)-analysis ; Calcium ; Phosphorus ; Dentinogenesis ; Biomineralization ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The subcellular distribution of the inorganic elements calcium (Ca) and phosphorus (P) was studied in the first-formed dentin matrix during initial mineralization in neonatal rat molars. This most peripheral matrix region is comprised of a proteoglycan-rich ground substance, interwoven by a collagenous network, matrix vesicles, aperiodic fibrils derived from the dental basal lamina, and apical odontoblastic cell processes. All matrix components may possibly serve as templets for mineral deposition during initial calcification of first-formed mantle dentin and predentin. By means of the very sensitive ESI-analysis we studied the subcellular localization of Ca and P and their possible association with distinct organic extracellular matrix components and odontoblasts. Ca-signals were found in the ground substance, at striated collagen fibrils and plasma membranes of odontoblasts in the cuspal early matrix region, but occurred only sparsely in the ground substance of the more distal matrix region where odontoblast processes attach to aperiodic fibrils of the dental basal lamina. Ca was generally absent in matrix vesicles. In contrast, P-signals were found in matrix vesicles, at aperiodic fibrils and at the plasma membranes of odontoblasts. Ca and P co-localized at striated collagen fibrils (type I or II). These results suggest that striated collagen fibrils might serve as primary deposition sites for calcium phosphate during early biological calcification of organic extracellular macromolecules.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 159 (1989), S. 501-508 
    ISSN: 1432-136X
    Keywords: Calcium ; Embryos ; Phosphorus ; Turtles ; Water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Eggs of common snapping turtles (Chelydra serpentina) were incubated on wet (−150 kPa water potential) and dry (−950 kPa) substrates in a laboratory study assessing the effects of the hydric environment on patterns of mobilization of calcium and phosphorus by developing embryos. We found that embryos developing in wet environments withdrew nutrients from their yolk faster, grew more rapidly, and incubated longer than embryos exposed to dry environments. Turtles developing in both environments absorbed calcium from the yolk at similar rates and depleted the yolk of almost its entire reserve of calcium prior to hatching. Calcium withdrawn from the yolk was supplemented with calcium mobilized from the eggshell, but embryos in wet environments obtained substantially more calcium from the eggshell than did those in dry settings. Embryos obtained all of the phosphorus used in skeletogenesis from the yolk, but those incubating in wet environments mobilized phosphorus from this compartment more rapidly than did those in dry settings. Exposing embryonic snapping turtles to wet environments apparently allows them to make more efficient use of the transitory source of calcium in the eggshell than is possible in dry environments. However, the residual yolk in hatchlings from both wet and dry environments contains too little calcium to support the growth of hard and soft tissues in neonates at rates similar to those characterizing the growth phase of development in embryogenesis.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 77 (1988), S. 506-514 
    ISSN: 1432-1939
    Keywords: Carbohydrate ; Growth form ; Nitrogen ; Phosphorus ; Tundra
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In a survey of 28 plant species of 6 major growth forms from Alaskan tundra, we found no consistent difference among growth forms in the chemical nature of stored reserves except for lichens and mosses (which stored C primarily as polysaccharides) and shrubs (which tended to store C more as sugars than as polysaccharides). Forbs and graminoids showed particularly great diversity in the chemical nature of stored reserves. In contrast, C, N, and P chemistry of leaves was strikingly similar among all species and growth forms. Concentrations of stored reserves of C, N, and P were highest and showed greatest seasonal fluctuations in forbs and graminoids but were relatively constant in evergreen shrubs. From this information, we draw three general conclusions: (1) the photosynthetic function of leaves strongly constrains leaf chemistry so that similar chemical composition is found in all species and growth forms: (2) the chemical nature of storage reserves is highly variable, both within and among growth forms; (3) the concentration and seasonal pattern of storage reserves are closely linked to growth-form and reflect growth-form differences in woodiness, phenology, and relative dependence upon concurrent uptake vs. storage in support of growth.
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  • 12
    ISSN: 1432-1939
    Keywords: Photosynthesis ; Nitrogen ; Phosphorus ; Nutrient use efficiency ; Pinus strobus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In white pine (Pinus strobus) seedlings grown in five forest soils from New York State, net photosynthetic capacity (Amax) plant-1 was correlated with total foliar N plant-1 (r 2=0.57), but was more highly correlated with total foliar P plant-1 (r 2=0.82). There was no relationship (r 2〈0.01) between Amax [g leaf]-1 and foliar N [g leaf]-1 for the pooled data set, but there was a significant (P〈0.001), but weak (r 2=0.20) positive relationship between Amax [g leaf]-1 and foliar P [g leaf]-1 across all soils. However, within two of the five soils leaf N concentration was a significant (P〈0.05) determinant of photosynthetic capacity. Due to differences in soil nutrient availabilities a large range in foliar P:N ratio (0.02–0.15) was observed, and the proportion of leaf P:N appeared to control Amax [g leaf N]-1. Whole plant nitrogen (NUE) and phosphorus (PUE) use efficiencies were well correlated with whole plant P:N ratio. In addition, NUE was well correlated with Amax [g leaf N]-1 and PUE was well correlated with Amax [g leaf P]-1. However, NUE was not well correlated with PUE, and Amax [g leaf N]-1 was not well correlated with Amax [g leaf P]-1. These results indicated that P and/or N limitations were important components of photosynthetic nutrient relations in white pine grown in these five soils and suggest that both P and N and their proportions should be considered in analyses of photosynthesis-nutrient relations.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Environmental management 12 (1988), S. 539-553 
    ISSN: 1432-1009
    Keywords: Coastal embayments ; Eutrophication ; Nitrogen ; Phosphorus ; Coastal lagoons ; Groundwater ; Septic tanks ; Nutrient loading
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Nutrient concentrations in Buttermilk Bay, a coastal embayment on the northern end of Buzzards Bay, MA, are higher in the nearshore where salinities are lower. This pattern suggests that freshwater sources may contribute significantly to nutrient inputs into Buttermilk Bay. To evaluate the relative importance of the various sources we estimated inputs of nutrients by each major source into the watershed and into the bay itself. Septic systems contributed about 40% of the nitrogen and phosphorus entering the watershed, with precipitation and fertilizer use adding the remainder. Groundwater transported over 85% of the nitrogen and 75% of the phosphorus entering the bay. Most nutrients entering the watershed failed to reach the bay; uptake by forests, soils, denitrification, and adsorption intercepted two-thirds of the nitrogen and nine-tenths of the phosphorus that entered the watershed. The nutrients that did reach the bay most likely originated from subsoil injections into groundwater by septic tanks, plus some leaching of fertilizers. Buttermilk Bay water has relatively low nutrient concentrations, probably because of uptake of nutrients by macrophytes and because of relatively rapid tidal flushing. Annual budgets of nutrients entering the watershed showed a low nitrogen-to-phosphorus ratio of 6, but passage of nutrients through the watershed raised N/P to 23, probably because of adsorption of PO4 during transit. The N/P ratio of water that leaves the watershed and presumably enters the bay is probably high enough to maintain active growth of nitrogenlimited coastal producers. There is a seasonal shift in N/P in the water column of Buttermilk Bay. N/P exceeded the 16∶1 Redfield ratio during midwinter; the remainder of the year N/P fell below 16∶1. This suggests that annual budgets do not provide sufficiently detailed data with which to interpret nutrient-limitation of producers. Further, some idea of water turnover is also needed to evaluate impact of loading rates. Urbanization of watersheds seems to increase loadings to nearshore environments, and to shift the nutrient loadings delivered to coastal waters to relatively high N-to-P ratios, potentially stimulating growth of nitrogen-limited primary producers.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 5 (1988), S. 313-316 
    ISSN: 1432-0789
    Keywords: Nematicide ; Phosphorus ; Subleaflet P ; Tropeptic Eutrustox ; Leucaena leucocephala ; VA mycorrhiza ; Glomus aggregatum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Concentrations of phenamiphos ranging from 0 to 40 μrg/g soil were established in a typical Oxisol (Tropeptic Eutrustox), inoculated or uninoculated with Glomus aggregatum. The effect of the nematicide on the development of vesicular-arbuscular mycorrhizal (VAM) symbiosis was evaluated in the greenhouse using Leucaena leucocephala as an indicator host plant. Treatment of soil with phenamiphos did not have a significant influence on the development of mycorrhizal activity measured in terms of subleaflet phosphorus concentrations. Similarly, the nematicide did not have an adverse effect on the level of mycorrhizal colonization or on the P content of shoots, as determined at the time of harvest. However, shoot dry weight was adversely influenced by phenamiphos when the chemical was applied to the uninoculated soil at 20 μg/g soil or higher, and when it was applied to the inoculated soil at 40 μg/g soil. It is concluded that phenamiphos is not likely to influence the growth of Leucaena or its symbiotic association with VAM fungi if the concentrations applied do not exceed levels known to suppress nematodes.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 107 (1988), S. 273-278 
    ISSN: 1573-5036
    Keywords: available P. organic amendments ; pH ; Phosphorus ; residue management Volcanic ash-influenced soils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Mission silt loam, (coarse-silty, mixed frigid Andic Fragiochrepts) is a forest soil in the Pacific Northwest which has a weathered ash horizon derived from volcanic eruptions in the Cascade Mountain Range. The major production problem for this soil is P fixation due to the weathered volcanic ash. Alternatives to large additions of fertilizer P are considered important in management of this and related soils. The objective of this work was to study the infuence of organic amendments on soil pH and extractable P in Mission soil. Alfalfa, (Medicago sativa L.) mixed conifer bark or sawdust was added at 4.8% w/w soil as a surface or incorporated treatment. In incubation experiments, both extractable P and soil pH were significantly increased over time for both surface and incorporated amendments. The majority of P mineralized from surface applied alfalfa remained in the surface 0–2 cm of the soil regardless of incubation period. Conversely, a uniform increase in P occurred throughout the 18 cm soil depth when sawdust was surface applied. The change in extractable P with sawdust addition was equivalent to 61 mg P kg−1 soil as soluble inorganic material. Soil pH increased rapidly in proximity to surface applied alfalfa while bark and sawdust affected the soil increasingly with time regardless of placement.
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 170 (1988), S. 19-34 
    ISSN: 1573-5117
    Keywords: Phosphorus ; mineral ; soil ; sediment ; sorption ; transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The geochemistry, availability and abundance of different forms of phosphorus in soil, water and sediments are reviewed. The present knowledge of phosphorus pathways in ecosystems and their regulation is discussed. In a drainage basin, anthropogenic phosphorus is brought into the system mainly as fertilizers and detergents. Sewer systems and outwash processes transfer the phosphorus from the terrestrial environment to the aquatic part of the ecosystem where an accumulation occurs in the sediments of the watercourse. A great part of the phosphates in soil is sorbed to soil particles or incorporated into soil organic matter. The release and export of phosphorus from uncultivated soil is a function of the geology and soil composition, but also of the air temperature, precipitation and the hydrological condition, pH etc. The solubility of phosphates is controlled by either sorption-desorption or precipitation-dissolution reactions depending on the environment in the soil or sediments. In soil and sediments with large amounts of iron and aluminium hydrous oxides, sorption-desorption reactions are largely responsible for determining the level of orthophosphate in the solution at equilibrium. Algal availability of phosphorus associated with soil-derived materials present in aquatic systems deserves more research. In addition, processes responsible for transport of phosphorus from cropland to aquatic systems and chemical and microbial transformations of phosphorus in lakes and streams deserve more attention.
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  • 17
    ISSN: 1573-5117
    Keywords: Phosphorus ; P-32 ; bluegill ; biological turnover constant ; radioactive tracer study ; specific activity measurements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The biological turnover constant for phosphorus was determined in muscle and five other sections of bluegill. Bluegill of average weight 121 g were maintained in a large flowthrough system at 22°–16°C and fed worms, Eisenia foetida, at two feeding levels, ad lib. (which averaged 2.6 g/d per 100-g fish, wet weight), and 1.5 g/d per 100-g fish. The daily phosphorus intakes at the two levels per 100-g fish were 3.1 and 1.8 mg. The average phosphorus concentration was 2.4 mg/g in muscle and 15.4 mg/g in the whole fish. Worm food was spiked with P-32 at increasing daily increments to balance radioactive decay. The radioactive worms were fed daily to the bluegill during the P-32 accumulation period of 51 days. For the next 28 days of depuration, nonradioactive worms were fed. Sets of three bluegill were collected at approximately weekly intervals, sectioned and analyzed for P-32 and phosphorus. All data were reported as specific activity in tissue relative to specific activity in feed, with P-32 count rates corrected for its 14.3-day half life. Phosphorus turnover constants were obtained by three approaches: (1) from the relative specific activity measured near steady state; (2) by fitting an equation for a 1-compartment model to the accumulation and depuration data; and (3) by fitting an equation for a simplified 2-compartment model to the depuration data. The biological turnover constant calculated with all three approaches was 0.004 d−1 for phosphorus in muscle of bluegill fed ad lib.
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  • 18
    ISSN: 1573-5117
    Keywords: Phytoplankton ; Subtropical Lake ; Nitrogen ; Phosphorus ; Nutrient enrichment ; Chlorophyta ; Flagellates ; Cyanophyta ; Bacillariophyta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A series of water samples from Lake Kinneret was supplemented with 100 µM N (as NH4 or as NO3 and/or 10 µM orthophosphate-P. The yield of phytoplankton both as chlorophyll and in cell numbers of major species was determined after a two-week incubation. During these experiments, some of the algae present initially never multiplied (e.g. Peridinium and Peridiniopsis spp. Cryptomonas spp., Rhodomonas spp. and Crysochromulina parva); others e.g. Anomoeoneis exilis, Synedra sp., Chlamydomonas sp., Elakatothrix gelatinosa), undetected in the original sample, grew out during the incubation. Chlorophyte species (the majority of commonly observed forms in the lake) responded most readily to added nutrients. The results of these enrichment experiments were related to the long-term record of phytoplankton populations observed in the lake and suggest that through summer and fall, when ambient levels of both P and N are minimal, P was generally, but not always, the most limiting nutrient for algal growth. In the spring, after the decline of the Peridinium bloom, P appeared to be limiting the growth of Chlorophyta. Although most algal species grew equally well on NH4 or NO3, some species appeared to respond preferentially either to the former (Coelastrum, Chodatella) or to the latter (Chroococcus, Anomoeoneis) source of N.
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  • 19
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    Research in experimental medicine 188 (1988), S. 139-149 
    ISSN: 1433-8580
    Keywords: Intestinal transport ; 1,25 (OH)2D3 ; Calcium ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The unidirectional ileal transport of calcium (Ca) and inorganic phosphorus (Pi) of rats was measured in vitro with the modified Ussing technique. Animal preparation included 5/6 nephrectomy and EHDP treatment. They were compared to controls as well as to 1,25 (OH)2D3 supplemented rats. The results show that the ileum is a secretory organ for Ca and Pi, the serosa to mucosa transport (Jsm) exceeds the mucosa to serosa transport (Jms). Ca and Pi transport in sm direction is 1,25 (OH)2D3 independent but exhibits a mutual strong correlation. Our observations together with published data are in favor of mainly paracellular, non electrogenic sm transport of both ions. However, the factor controlling sm transport of Ca and Pi remains unidentified. The mucosa to serosa transport (Jms) in the ileum is low for both ions. Ca ms is stimulated by 1,25 (OH)2D3, Pi ms is unchanged.
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  • 20
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    Springer
    Rheologica acta 27 (1988), S. 52-60 
    ISSN: 1435-1528
    Keywords: Polymerization ; sol-geltransition ; breakpoint ; pH value ; polysilicic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Abstract The rheological behaviour of silicic acid in aqueous solutions was studied over a period of time for pH values between 6 and 8 at the concentration 10 g ⋅ 1−1, and at pH = 8 for different concentrations varying from 0.5 to 10 g ⋅ 1−1. The shear stress-shear rate curves indicate a very complex character of rheological behaviour. Its analysis with respect to the influence of time, pH and concentration contributes to the knowledge of the structure of the polymer during the process of gel formation. It is shown that the inital shear-thickening behaviour of the colloïdal sol at low concentrations is followed by a shear-thinning behaviour under conditions of polymerization of the silicic acid. The sol-gel transition is marked by a breakpoint. When measurements pass beyond this point, plastic flow behaviour is observed because of the shear induced formation of amorphous silicic aggregates. All rheological processes of silicic acid sols are intensified at pH = 8.
    Notes: Résumé Le comportement rhéologique de sols d'acide silicique a été examiné au cours du temps à des pH compris entre 6 et 8 à la concentration de 10 g ⋅ 1−1 de silice, et à pH = 8 à des concentrations variant entre 0,5 et 10 g ⋅ 1−1. Les courbes d'écoulement révélent un comportement rhéologique complexe. L'analyse des rhéogrammes en fonction du temps, du pH et de la concentration contribue à la connaissance de l'état structural du polymère au cours de la formation du gel. Il ressort que le comportement initialement rhéoépaississant aux faibles concentrations correspondant à l'état d'une solution colloïdale, laisse place à un écoulement rhéofluidifiant dans les conditions favorables á la polymérisation de l'acide silicique. La transition sol-gel est marquée par un breakpoint; en prolongeant les mesures on observe un comportement plastique dû à l'apparition d'agrégats sous l'effet du cisaillement. Tous les processus rhéologiques se trouvent exacerbées à pH = 8.
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  • 21
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    Protoplasma 145 (1988), S. 73-81 
    ISSN: 1615-6102
    Keywords: Intermediate filament structure ; Intermediate filament assembly ; Desmin ; Keratins ; Neurofilaments ; Nuclear lamins ; Cytoskeleton ; Electron microscopy ; Polymerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 22
    ISSN: 0570-0833
    Keywords: Organonickel compounds ; Polymerization ; Hydrogenation ; Homogeneous catalysis ; Catalysis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: One hundred years of organonickel chemistry have generated a wealth of new knowledge and a history of examples of accidental discoveries which have finally led to industrial applications. The historical development is associated with the names of Mond, Sabatier, Reppe and Ziegler and, with the methods and techniques available today, many of the original discoveries and unsolved problems are attracting renewed attention. For example, 70 years were to go by before a synthesis first conceived by Sabatier could finally be realized. The path leading from nickel-catalyzed hydrogenation to highly enantioselective homogeneous catalysts is one of the contributions to organonickel chemistry which is described here.
    Additional Material: 19 Ill.
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  • 23
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    Applied Organometallic Chemistry 2 (1988), S. 533-537 
    ISSN: 0268-2605
    Keywords: Polymerization ; ethynylferrocene ; conductivity ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The catalytic activity of the [Rh(cod)Cl]2 complex (cod = cis, cis-cyclo-octa-1,5-diene) with respect to the polymerization of ethynylferrocene (EFc) was examined. A good yield (about 80%) of polyethynylferrocene (PEFc) was obtained in benzene by addition of sodium hydroxide as co-catalyst. PEFc was insoluble in most organic solvents. The conductivity (s̰) of the undoped polymer is about 10-11 ohm-1 cm-1; upon doping PEFc with iodine in tetrahydrofuran the conductivity can be increased to 10-100 ohm-1 cm-1. The influence of other doping agents was also examined.
    Additional Material: 2 Ill.
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  • 24
    ISSN: 1432-2013
    Keywords: Cholesterol ; 1,25 Vitamin D3 ; Calcium ; Phosphorus ; Calcemia ; Hypocholesterolemia ; 7-Dehydrocholesterol reductase ; Epidermis ; Rat UV radiation ; Skin vitamin D3 synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Vitamin D3 is generated in skin by UV irradiation of 7-dehydrocholesterol (7-DEHC). Whether the 7-DEHC amount in skin affects vitamin D3 formation, and thereby the plasma level of 25-hydroxyvitamin D3 (25[OH]D3) is not known. In the present work we report on the influence on vitamin D and Ca metabolism of a new hypocholesterolemic agent, HCG-917 (0-2-[hydroxy-3-]N′-(2-chlorophenyl)-N-piperazinyl-1-[propyl]-4-chloro-benz-aldoxim-hydrochloride) which inhibits 7-DEHC reductase and thereby increases skin 7-DEHC. Rats were treated with HCG 917 (0.3 and 5.0 mg/kg, orally) for 13 days. HCG 917 caused a dose-dependent decrease in cholesterol and concomitant accumulation of 7-DEHC in plasma and skin. In skin, 7-DEHC was: control: 1.05±0.20; HCG 917, 0.3 mg/kg: 1.41±0.22; HCG 917, 5.0 mg/kg: 2.35±0.35 mg/g. At a dose of 0.3 mg/kg, HCG 917 had no significant influence on the plasma level of neither 25(OH)D3 nor 1,25(OH)2D3. However, at a dose of 5.0 mg/kg, HCG 917 induced a significant increase in plasma 25(OH)D3 (control: 36.2±2.2; HCG 917 5.0 mg/kg: 57.6±6.5 nmol/l) and a slight but not significant rise in 1,25(OH)2D3. Calcium balance studies indicated that HCG 917 did not influence intestinal Ca absorption nor urinary Ca excretion. At a dose of 5.0 mg/kg HCG 917 slightly induced a decrease in total plasma Ca. In conclusion, HCG 917 treatment can induce a significant rise in skin 7-DEHC with an increase in plasma 25(OH)D3. These results suggest that variation in the skin level of 7-DEHC can directly influence the cutaneous production of vitamin D3 and thereby the vitamin D status of the organism.
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  • 25
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    Journal of molecular evolution 25 (1987), S. 191-196 
    ISSN: 1432-1432
    Keywords: Glyceroyl thioester ; Polymerization ; Polyester ; Oligoglyceric acid ; Thioester ; Prebiotic chemistry ; Molecular evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The autocondensation of the glyceroyl thioesterS-glyceroyl-ethanethiol yielded oligoglyceric acid. The rates of autocondensation and hydrolysis of the thioester increased from pH 6.5 to pH 7.5 in 2,6-lutidine and imidazole buffers. Autocondensation and hydrolysis were much more rapid in imidazole buffers than in 2,6-lutidine buffers of the same pH. The efficiency of ester bond synthesis was about 20% for 40 mMS-glyceroylethanethiol in 2,6-lutidine and imidazole buffers near neutral pH. The size and yield of the oligoglyceric acid products increased when the concentration of the thioester was increased. The relationship of these results to prebiotic polymer synthesis is discussed.
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  • 26
    ISSN: 1432-1939
    Keywords: Ericaceae ; Nitrogen ; Phosphorus ; Deciduous ; Evergreen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Aboveground growth, reproduction, and foliar nitrogen and phosphorus contents of two ericaceous shrub species were compared over two seasons in (a) an undisturbed shrub bog (pocosin), and (b) a factorial fertilization design in which three levels each of nitrogen and phosphorus were added in all possible combinations. One species, Zenobia pulverulenta, is deciduous whereas the other species, Lyonia lucida, is evergreen. In the nutrient-poor undisturbed pocosin the two species exhibited similar foliar nitrogen and phosphorus concentrations and aboveground growth rates. Neither species flowered. In response to nutrient-addition Zenobia increased growth rates more than Lyonia. Foliar phosphorus concentrations of both species increased in response to enhanced phosphorus availability. in the first season neither species flowered in any treatment. In the second season Zenobia flowered only in the fertilized plots, with the most flowering in the high phosphorus treatments. I conclude that, by virtue of high growth rates and efficient use of nutrients and despite differences in leaf phenology and morphology, both Lyonia and Zenobia are successful in a competitive community under conditions of extremely low phosphorus availability. However, unlike Lyonia, Zenobia can take advantage of temporarily increased nutrient availability, which occurs following fire in the pocosin, to increase growth and reproduction.
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  • 27
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    Oecologia 74 (1987), S. 370-376 
    ISSN: 1432-1939
    Keywords: Costa Rica ; Miconia ; Piper ; Nitrogen ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Six speices of shrubs and one large herb with contrasting life history patterns were used as bioassays of nutrient availability in a Costa Rican lowland rain forest soil. Growth responses of the herb (Phytolacca rivinoides, Phytolaccaceae) confirmed soil measurements indicating high availability of N and potentially limiting levels of P, K, Mg and Ca. Growth responses of the shrub species (Miconia spp., Melastomataceae and Piper spp., Piperaceae) to a complete nutrient fertilizer were generally less than that of Phytolacca. Lack of a strong shrub response to +P fertilization is probably due to mycorrhizal associations and slower growth rates of woody species. In general, increased growth did not occur at the expense of phenolic production in the leaves. The results emphasize that assessment of specific nutrient limitations to plant growth vary depending on species selected for the bioassay, even among species from the same community.
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  • 28
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    Oecologia 73 (1987), S. 268-271 
    ISSN: 1432-1939
    Keywords: Foliar nutrients ; Resorption ; Succession ; Nitrogen ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Leaves were sampled in a successional, southern Appalachian forest to estimate autumn foliar nutrient dynamics. Resorption of N and P in a successional forest equaled, or exceeded, resorption estimates for a more mature control forest. Foliar nutrient leaching was not sufficient to account for changes in autumn leaf N, P, Ca and Mg concentrations. The resorption process conserves nutrients by reducing nutrient losses from leaching and litter-fall, thereby closing the nutrient cycle in successional forests. We hypothesize that rapid recovery of primary productivity early in forest regeneration is the result of maximum nutrient resorption of limiting nutrients. Implications of these results for successional nutrient cycling theory are discussed.
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  • 29
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    Biology and fertility of soils 5 (1987), S. 230-234 
    ISSN: 1432-0789
    Keywords: Earthworm casts ; Microbial respiration ; Microbial biomass ; Nitrogen ; Phosphorus ; Aporrectodea caliginosa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Microbial respiration, microbial biomass and nutrient requirements of the microflora (C, N, P) were studied in the food substrate (soil taken from the upper 3 cm of the mineral soil of a beech wood on limestone), the burrow walls and the casts of the earthworm Aporrectodea caliginosa (Savigny). The passage of the soil through the gut caused an increase in soil microbial respiration of about 90% over a 4-week period. Microbial biomass was increased only in freshly deposited casts and decreased in aging faeces to a level about 10% lower than in soil. Microbial respiration of the burrow walls was only increased over a shorter period (about 2 weeks). The microflora of the soil and the burrow walls was limited by P, whereas in earthworm casts, microbial growth was limited by the amount of available C. In aging faeces the P requirement of the microflora increased and approached that of the soil. Immobilization of phosphate in earthworm casts is probably caused by mainly abiotic processes. C mineralization by soil microflora fertilized with glucose and P was limited by N, except in freshly deposited casts. Ammonium, not nitrate, was responsible for this process. N dynamics in earthworm casts are discussed.
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  • 30
    ISSN: 1573-0867
    Keywords: Phosphorus ; potassium ; fertilizer placement ; triple-superphosphate ; partially acidulated phosphate rock ; hybrid squash ; Cucurbita maxima L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two experiments examined options for reducing the inputs of P and K fertilizers for hybrid squash (Cucurbita maxima L.) at Pukekohe, New Zealand. The first experiment examined the effects of elevating the NaHCO3-soluble P from 32 to 130 mg kg−1 and the exchangeable K from 140 to 350 mg kg−1 within strips from 0 to 0.75 m around rows of hybrid squash planted 1.5 m apart. From both P and K, crop yield increased as the width of the fertilized strip was increased up to 0.25 m, while wider fertilized strips had no further effect. These results followed similar effects on plant dry matter and tissue P or K concentration during early growth, and are explained in terms of the P and K accumulation by the crop, the decline during growth of the sensitivity of the crop to soil P and K fertility associated with declining rates of P and K uptake per unit length of root. Implications for fertilizer management for hybrid squash are also discussed. The second experiment compared the effects of partially acidulated phosphate rock and triple-superphosphate on soil P fertility, growth and yield of hybrid squash. Partially acidulated phosphate rock had smaller effects than those of triple-superphosphate on NaHCO3-soluble P levels in the soil, plant dry weight and tissue P concentration soon after emergence, and subsequently crop yield. On average, partially acidulated phosphate rock increased crop yield by about 70% of that following the application of the same quantity of P as triple-superphosphate. This lower effectiveness of partially acidulated phosphate rock for hybrid squash is explained in terms of its lower solubility and hence smaller effect on NaHCO3-soluble P in the soil during early growth, when the crop is most sensitive to soil P fertility.
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  • 31
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    Plant and soil 97 (1987), S. 369-379 
    ISSN: 1573-5036
    Keywords: Bark ; Calcium phosphate ; Eucalyptus marginata ; Fertilizer ; Leaf ; Lignotuber ; Phosphorus ; Shoot growth ; Wood
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Effects of calcium phosphate supply on plant dry matter and phosphorus concentrations of parts of jarrah (Eucalyptus marginata) seedlings grown in a lateritic topsoil from the jarrah forest were examined in two glasshouse trials. Phosphorus deficiency depressed root and shoot dry weights and severely deficient leaves were smal and purple with prominent red major veins. Phosphorus deficiency severely reduced stem phosphorus levels (0.5% to 0.02%, experiment 1). Phosphorus concentrations were higher in bark than wood and the amount of phosphorus in the bark was sensitive to stem age and phosphate supply. Phosphorus adequate plants had bark phosphorus concentrations in the range 0.2–0.9% compared to 〈0.1% in deficient plants (experiment 2). Jarrah leaves accumulated dry matter up to 80 days after expansion and some leaves exported phosphorus during this period. Bark analysis may therefore be preferable to leaf analysis for detecting phosphorus deficiency in this species.
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  • 32
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    Plant and soil 98 (1987), S. 99-109 
    ISSN: 1573-5036
    Keywords: Allelopathy ; Ferulic acid ; Magnesium ; Mineral content ; Phosphorus ; PotassiumSorghum bicolor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Two week old sorghum seedlings (Sorghum bicolor L. Moench) were treated with ferulic acid added to the nutrient solution. Effects on tissue concentration of P, K, Mg, Ca, Fe, and Zn were evaluated after 3 and 6 days. Treatemnts of 0.25 mM ferulic acid approximated the growth inhibition threshold, and after 6 days 0.5 mM treated plants weighed less than controls. Both treatments reduced the P content of the roots and shoots at the 3- and 6-day harvests in three replicate experiments. Roots of treated plants at both harvests had a lower concentration of K and Mg. These reductions in P, K, and Mg were most extensive from the 0.5 mM ferulic acid regime. In some cases at both harvests, shoot K was lower and Mg was higher than control tissue. Ferulic acid effects at the 3-day harvest included an elevation of Ca and depression of Fe in shoots. Changes in nutrient content preceded measurable differences in plant weight. These data indicate that one mechanism of growth inhibition by this allelochemical may be an alteration of nutrient balance.
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  • 33
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    Plant and soil 98 (1987), S. 363-375 
    ISSN: 1573-5036
    Keywords: Ammonium ; Forest soil samples ; Nitrate ; pH ; Phosphorus ; Potassium ; Sample storage ; Seasonal variation ; Soil analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary This study was carried out in order to assess the importance of storage procedures and time of sampling for the results of routine chemical analyses of forest soils. Humus and mineral soil samples were collected at five-week intervals during two growing seasons from a sample plot in a coniferous forest in northern Sweden. The samples were either air-dried (+35°C) or frozen (−20°C). After a few months they were analysed for ‘easily available’ and ‘relatively available’ phosphorus (P-AL and P-HCl) and potassium (K-AL and K-HCl), ammonium, nitrate and pH. In some cases there was a significant difference between the two sample treatments. In humus, the concentrations of P-AL and NH4-N were 51% and 76% higher in samples which had been frozen than in those which had been air-dried while the concentrations of NO3-N were 75% higher. in air-dried than in frozen samples. In mineral soil samples, 21–64% higher concentrations of K-AL were found in frozen samples compared to air-dried and 80–427% higher concentrations of NO3-N in air-dried than in frozen samples. No distinct seasonal variations were found for any of the parameters.
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  • 34
    ISSN: 1573-5036
    Keywords: Copper ; Dazomet ; Field experiment ; Leek ; Phosphorus ; Pretransplant inoculation ; VA mycorrhiza ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Leek plants were preinoculated with a mixed inoculum ofGlomus caledonium, Glomus fasciculatum andGlomus sp., and transplanted to Dazomet disinfected and untreated field plots of moderate P deficiency. Successive harvests were made until 99 days after transplanting. Preinoculated leeks attained marketable weights 25 days earlier than uninoculated leeks from untreated soil and their final dry matter yields were 5.7 and 1.5 times as high as those of uninoculated leeks from disinfected and untreated soil, respectively. Phosphorus concentration in preinoculated leeks remained highest for at least 22 and 75 days after transplanting in untreated and disinfected soil, respectively. Preinoculation had a similar, although smaller, influence on Cu and Zn concentrations. Infection levels produced by introduced and indigenous VA endophytes in leeks reached plateaus of 90% and 40%, respectively, 47 days after transplanting. It is concluded that VAM is essential to leeks grown in moderately P deficient soils, and the potential for inoculating seedlings in commercial leek production is discussed.
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  • 35
    ISSN: 1434-9949
    Keywords: Senile Osteoporosis ; Phosphorus ; Salmonn Calcitonin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Twenty-five patients with radiological and clinical evidence of osteoporosis were studied. Nineteen patients received oral phosphorus at a dose of 1,000 mg/die for 10 days followed by salmon calcitonin (100 U MRC/die) for 20 days. Six patients received only oral calcium at a dose of 1,000 mg/die). In the first group, a significant increase in serum osteocalcin and parathyroid hormone, after administration of phosphorus and persisting after treatment with salmon calcitonin, was found. No variation in the controls was observed. In a later study, a significant increase in serum 1,25 dihydroxyvitamin D (1,25(OH)2D3), after receiving phosphorus and persisting after salmon calcitonin, was demonstrated. In accordance with the authors' results, phosphorus could be considered a useful activator of bone formation and this stimulus by parathyroid hormone was mediated. Finally, the positive effects of phosphorus on circulating 1,25(OH)2D3 must be considered for a good treatment protocol of osteoporosis.
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  • 36
    ISSN: 0570-0833
    Keywords: Polyphosphorus compounds ; Phosphorus ; Polyphosphanes ; Phosphanes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In contrast to the numerous known and often technically important mono- and diphosphorus compounds with phosphorus in its maximum oxidation state, polyphosphorus compounds led only a shadowy existence up to about twenty years ago. One of the reasons for this was the properties of such compounds, which made their handling and structural characterization difficult. This problem was solved by the development of modern preparative techniques and, especially, by the further methodological development of nuclear magnetic resonance spectroscopy. Thus, a fascinating new branch of phosphorus chemistry has been opened up in recent years. The first comprehensive review on this subject was published five years ago. Since then, research on this “element-near” chemistry of phosphorus has produced further impressive advances with the result that a surprisingly large variety of compounds with skeletons consisting of chains or rings of phosphorus atoms is known today. However, the recent observation of the spontaneous formation of the “aromatic” pentaphosphacyclopentadienide ion, P5-, during the synthesis of phosphorus-richer polyphosphides from phosphorus-poorer compounds in solution and the discovery of the inversion of phosphorus in tetra- and pentacyclic organophosphanes demonstrate that this field is still capable of producing surprises.
    Additional Material: 7 Ill.
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  • 37
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    Applied Organometallic Chemistry 1 (1987), S. 171-176 
    ISSN: 0268-2605
    Keywords: Condensation ; Polymerization ; Silyladamantane ; Thermal stability ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,3-bis(Dimethylhydroxysilyl)adamantane(I) has been prepared. Thermal condensation polymerization of this monomer yields poly-1,3-adamantyl-1,1,3,3-tetramethyldisiloxane. Condensation of I with bis(dimethylamino)dimethylsilane or 1,3-bis(dimethylamino)-1,1,3,3-tetramethyldisiloxane gave the expected 1,3-adamantyl dimethylsiloxane copolymers (II and III) respectively. These polymers have been characterized by 1H,13C, and 29SiNMR as well as GPC and TGA. They have unusually high thermal stability.
    Additional Material: 5 Ill.
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  • 38
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    Oecologia 70 (1986), S. 128-131 
    ISSN: 1432-1939
    Keywords: Lolium ; Nitrogen ; Nutrient transfer ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary It is known that nitrogen and phosphorus can be transferred from one living plant to another, but it is not known whether the amounts transferred are large enough to influence the growth of the species in the field. Two Lolium perenne plants were grown per pot of unfertilized soil. During 25 weeks one plant (the ‘donor’) in each pot was fed nutrients through leaves; donors in control pots received only water. The ‘receiver’ plants which shared a pot with the nutrient-fed donors increased significantly, compared with the controls, in leaf number and concentration of phosphorus, though not in concentration of nitrogen, potassium, calcium or magnesium. The rate of phosphorus transfer agreed well with previous results using 32P. The results are compared with rates of phosphorus uptake in the field. It is concluded that nutrient transfer could have an influence on the balance between coexisting species in the field, but probably the influence will be small.
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  • 39
    ISSN: 1440-1703
    Keywords: Antarctica ; Carbon ; Moss community ; Nitrogen ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The distributions of carbon, nitrogen and phosphorus in a moss community-soil system developed on a naked region in Rundvågskollane (69050'S, 39009'E), East Antarctica, were investigated in order to analyze the flow of matter in an Antarctic terrestrial ecosystem. 1) The moss community was formed from many moss blocks of different sizes and was composed ofBryum pseudotriquetrum (Hedw.) Gaertn., Meyer et Scherb.,Ceratodon purpureus (Hedw.) Brid. andGrimmia lawiana J. H. Willis. The surface of the community was covered with cyanobacteria. 2) It was estimated that nitrogen fixed by cyanobacteria flowed from these organisms to the moss and that little nitrogen was transported within the moss body. 3) A large amount of phosphorus existed in the soil. The moss community had a high phosphorus content although the amount itself was relatively little due to the small phytomass. 4) It seems that absorption of phosphorus from soil is difficult for moss, because of the paucity of water necessary for the movement of phosphorus and the suppressed growth of moss due to the arid conditions.
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  • 40
    ISSN: 1573-5036
    Keywords: Ammonium uptake ; Barley ; Brassica napus L. ; Buckwheat ; Cation-anion balance ; Fagopyrum esculentum Moench ; Hordeum vulgare L. ; Nitrate uptake ; Phosphorus ; Rape
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Absorption of nitrate and ammonium was studied in water culture experiments with 4 to 6 weeks old plants of barley (Hordeum vulgare L.), buckwheat (Fagopyrum esculentum L. Moench) and rape (Brassica napus L.). The plants were grown in a complete nutrient solution with nitrate (5.7±0.2 mM) or nitrate (5.6±0.2 mM) + ammonium (0.04±0.02 mM). The pH of the nutrient solution was kept at 5.0 using a pH-stat. It was found that phosphorus deficiency reduced the rate of nitrate uptake by 58±3% when nitrate was the sole N source and by 83±1% when both nitrate and ammonium were present. The reduction occurred even before growth was significantly impeded by P deficiency. The inhibition of the uptake of ammonium was less,i.e. ammonium constituted 10±1% of the total N uptake in the P sufficient plants and 30±5% in the P deficient plants. The reduction of nitrate absorption greatly decreased the difference between the uptake of anions and cations. It is suggested that P deficiency reduced the assimilation of NO 3 − into the proteins, which might cause a negative feedback on NO 3 − influx and/or stimulate NO 3 − efflux.
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  • 41
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    Plant and soil 92 (1986), S. 265-278 
    ISSN: 1573-5036
    Keywords: Bioavailability ; Bonding energy ; Flooded-drained ; Phosphorus ; Phosphorus sorption ; P uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Changes in P sorption and bioavailability were studied with 4 soils previously flooded and drained as occurs in rice-based cropping systems. Phosphorus sorption was measured at 15 and 119 days after drainage and the bioavailability of added and native soil-P was determined at 9, 16, 30, 45, 70 and 135 days in both flooded-drained and unflooded soils. The P sorptivity and bonding energy of sorption increased under flooded-drained soil conditions. At 119 days after drainage the P sorptivity and bonding energy of sorption decreased as compared to 15 days after drainage. The P sorptivity of the flooded-drained soils, however, did not reach the same levels as existed in the soils prior to flooding. The bioavailability of P during the drainage period remained low and did not measurably change up to 70 days after drainage. At 135 days after drainage the bioavailability of P increased significantly, but did not reach the level found in the corresponding unflooded soils.
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  • 42
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    Plant and soil 93 (1986), S. 373-382 
    ISSN: 1573-5036
    Keywords: Calcium ; Fertilizer ; Magnesium ; Nitrogen ; Nutrient content ; Phosphorus ; Pinus radiata ; Potassium ; Superphosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Nutrient contents of aPinus radiata stand, that is, aboveground tree, understorey, forest floor and soil to 200 mm depth, were estimated in a replicated fertilizer trial, treated 30 years previously. The fertilizer treatments were 0, 25, 50, 75 and 100 kg P/ha as broadcast superphosphate. Highly significant growth responses had been obtained to the applied P. Estimation of the P content of the stand showed that 129%, 89%, 72% and 67% of the applied P was found in the 25, 50, 75 and 100 kg P/ha treatments respectively. The larger losses of P at the higher application rates would explain the lack of increased response with the highest application rate, however, it also shows that significant quantities of P are still present after a period of 30 years, giving a basis for growth responses in the subsequent rotations. Elevated quantities of N, Ca, Mg and K were found in the treatments compared with the control and these could not be explained on the basis of atmospheric inputs. For the cations, uptake from deeper in the soil profile could explain most of the effect but not for the higher amounts of N which, in the case of the highest superphosphate treatment, amounted to an accumulation of 27 kg N/ha/yr. These nutrient changes together with increased soil organic matter contents are considered to have provided a long term increase to the site productivity.
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  • 43
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    Plant and soil 95 (1986), S. 361-377 
    ISSN: 1573-5036
    Keywords: glomus fasciculatum ; Glomus mosseae ; Glycine max ; Phosphorus ; Specific P Uptake Rate (SPUR) ; Vesicular-arbuscular mycorrhiza (VAM)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Soybean (Glycine max L. Merr. cv. Amsoy 71) plants were grown in a greenhouse in a soil very low in plant-available P, and plants were harvested 5 times over a 21-week growth period. Soybeans were inoculated with one of two species of VAM fungi or received daily one of three nutrient solutions of different P concentrations (0.0, 0.2, or 1.0mMP). Until week 9, the dry weights, leaf areas and developmental stage of soybeans inoculated withG. fasciculatum orG. mosseae were similar to the 1.0 or 0.2mMP-treated plants, respectively. Phosphorus concentrations were significantly lower in VAM plants at weeks 6 and 9 as compared to non-VAM soybeans given 1.0mMP, suggesting P input in VAM plants was immediately used for new growth. Total P input for VAM plants was linear over 21 weeks, and the average rate of P uptake for these plants was 0.19mg P d−1. Estimated specific P uptake rates (SPUR) for the mycorrhizae (VAM roots) were twice that of the control (0.0mMP) roots. The calculated SPURs forG. fasciculatum andG. mosseae hyphae were 95 and 120μg P g−1 VAM d−1 respectively, a 4 to 5 fold increase over non-inoculated roots, indicating more attention must be paid to P assimilation by VAM fungi in P-fixing substrates.
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  • 44
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    Plant and soil 95 (1986), S. 173-181 
    ISSN: 1573-5036
    Keywords: Apparent heat of sorption ; Bonding energy ; Flooded-drain ; Phosphorus ; Phosphate ; Sorption ; Temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effects of temperature and prior flooding of soil on P sorption were examined in 2 soils having a rice-based cropping system and showing an induced P deficiency problem in flooded rice-uplant crop rotations. The P sorption capacity of soil increased with increasing temperature as well as with prior flooding, the effects of the latter were, howerver, dominant. The bonding energy of sorption, calculated from the Langmuir isotherm, also increased with both temperature and prior flooding of soils, indicate that the effects of chemical changes associated with alternative anoxic and oxidized soil conditions are more significant in the P reversion process. The apparent heat of sorption reaction, calculated with the Freundlich isotherm and Van't Hoff's equation also increased due to prior flooding of soil.
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  • 45
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    Plant and soil 95 (1986), S. 191-200 
    ISSN: 1573-5036
    Keywords: Atmospheric input ; Douglas fir Fertilization ; Foliar analysis ; Forest nutrition ; N/P ratio ; Nitrogen ; Nutrient status ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A re-examination of earlier NPK fertilization experiments in Douglas fir stands on sandy soils shows the effects of high nitrogen input by air pollution during the last 10–15 years on plant nutrition at these sites. In 1960, experimental plots showed a positive growth reaction to nitrogen, phosphorus, and potassium fertilization. All suffered from severe phosphorus deficiency in 1984, low phosphorus in the needles was invariably accompanied by a high nitrogen content, with all N/P ratios between 20 and 30. The same conclusion emerges from an independent investigation of nutrient status of a selection of Douglas fir stands. Hence, if stand productivity and a balanced nutrient status of the trees is to be maintained, the increase in atmospheric input of nitrogen calls for supplementary fertilization. Given the current N/P ratios in the needles, a positive growth response to phosphorus fertilization is to be expected.
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  • 46
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    Plant and soil 93 (1986), S. 137-140 
    ISSN: 1573-5036
    Keywords: Calcium ; Magnesium ; Phosphorus ; Pinus caribaea ; Potassium ; Savanna ; Tap root
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The content of elements in needles ofPinus caribaea trees growing upon infertile savanna soils was analysed at 3 and 5 years after the tap roots of a subset of trees had been severed. No significant differences were found between the content of elements in treated and control trees, nor were significant differences found in increments of diameter of the trees over 5 years. It is concluded that this organ plays no significant nutritional role in the trees on these soils, and that tree growth can be achieved exclusively from atmospheric nutrient accessions and exchangeable nutrient reserves in the topsoil.
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  • 47
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    Plant and soil 93 (1986), S. 183-193 
    ISSN: 1573-5036
    Keywords: Ammonium phosphate ; Lactuca sativa L. ; Phosphorus ; Placement ; Potassium phosphate ; Root-shoot ratio ; Soil temperature ; Starter fertilizer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A pot experiment is described which investigated the effects of placing starter fertilizer, 1 cm beneath the seeds, on growth and nutrient uptake in lettuce seedlings at two soil temperatures (10°C and 20°C). At both temperatures the presence of starter fertilizer increased nutrient concentrations within the plants. At 20°C there was no growth response to the starter treatments. However, at 10°C there was a large response to the application of starter fertilizer. The best treatment was a combination of NH4H2PO4 and KH2PO4 which increased plant dry weight by 64% at 19 days from sowing. Nutrient deficiency caused a significant increase in the root length/shoot weight ratio of the control plants at 10°C. The responses to the starter were shown to be determined by the balance between the demand for nutrients from the shoots and the supplying power of the roots.
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  • 48
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    Plant and soil 96 (1986), S. 279-285 
    ISSN: 1573-5036
    Keywords: Mycorrhiza ; Phosphorus ; Plant growth ; Theobroma cacao
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effects of vesicular-arbuscular mycorrhiza (VAM) on the growth and phosphorus uptake of cocoa seedlings (Theobroma cacao L.) grown for 100 days in polythene bags, were studied at five levels of phosphorus fertilization in both steamed and unsterile Bungor Series soil (a fine clayey, kaolinitic isohyperthermic Typic Paleudult). The cocoa seedlings responded well to phosphorus fertilization and mycorrhizal treatments. Plants inoculated with VAM fungi (Gigaspora spp.) gave the most vigorous growth and higher phosphorus in the leaf tissues in unsterile soil compared to plants grown in steamed soil. However, the mycorrhizal effect was significantly more pronounced (P〈0.01) in plants grown in steamed than in unsterile soil. High levels of phosphorus application depressed mycorrhizal development. Phosphorus fertilizer applied at the rates of 250 and 500 ug g−1 soil gave maximum root colonization and spore counts in both soil types used.
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  • 49
    ISSN: 1573-5052
    Keywords: Africa ; Cameroun ; Gradient ; Korup ; Phosphorus ; Rain-forest ; Topography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract All living trees (≥30 cm gbh) were enumerated in 135 80×80 m plots, each subdivided into four 40×40 m subplots, and arranged along four 5 km transect lines in the Korup Forest Reserve, Cameroun. For each plot altitude, slope and the extent of permanent and seasonal swamps were recorded. Four hundred and eleven taxa were recognized of which 66% were identified to species. Mean tree density was 471 ha−1, basal area 27.6 m2 ha−1 and number of species per plot 75. The subfamily Caesalpinioideae (Leguminosae) was the most abundant family/subfamily in terms of basal area, but the Scytopetalaceae the most frequently represented, mainly on account ofOubanguia alata. Ten plots had at least three quarters of their area permanently swamped, and three, to a similar extent, were seasonally swamped. The ranges in sand, silt and clay content were 60–91, 0–24 and 4–20% respectively. The pH value, organic carbon content and nitrate-nitrogen concentration ranged between 4.0–5.8, 1.3–5.7% and 0–35 ppm respectively. The largest soil variations were in available phosphorus, range 2–29 ppm, and potassium, 38–375 ppm. Correspondence analysis ordination of all plots showed a major indirect floristic gradient correlated with increasing altitude, slope and soil phosphorus and potassium. Removal of the topographic effect by separate re-ordinations of four groups of plots at low, middle (2) and high altitude/slopes highlighted a strong correlation of the main floristic gradients of the middle altitude/slope groups with the concentration of available soil phosphorus. Direct gradient analysis using all plots with respect to available soil phosphorus concentration confirmed the indirect analyses. Individual species response to phosphorus were also shown by direct comparisons in the vegetation on plots of high and low available soil phosphorus concentration. Low available phosphorus soils (≤5 ppm) are strongly associated with species of the subfamily Caesalpinioideae, especially of the tribes Amherstieae and Detarieae. It is suggested that this result is probably due to the ability of these particular legume tribes to form associations with ectotrophic mycorrhizae.
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  • 50
    ISSN: 1573-5052
    Keywords: Africa ; Cameroun ; Douala-Edea ; Drainage ; Gradient ; Phosphorus ; Rain-forest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract All living trees (≥30 cm gbh) were enumerated in 104 80×80 m plots arranged along four transects in the Douala-Edea Forest Reserve Cameroun, a system of low-lying ancient coastal sand dunes interspersed by numerous streams and swamps. The extent of permanent and seasonal swamps was recorded for each plot. Two hundred thirty taxa were recognized of which 63% were identified to species. Mean tree density was 376 ha−1, basal area 31.0 m2 ha−1 and number of species per plot 39. The Olacaceae were the most abundant family in terms of basal area, but the Euphorbiaceae the most frequently represented. The most abundant species wasCoula edulis (Olacaceae). Twenty-two plots had most of their area permanently or seasonally swamped. Percentage sand, silt and clay ranged between 32–100, 0–64, 0–21% respectively. The ranges for other variables recorded were: pH (2.7–5.4), organic carbon (1.5–12.4%), available phosphorus (7–90 ppm) and potassium (28–188 ppm), and nitrogen (ammonium 4–40 ppm, nitrate 1–12 ppm). Classification of the plots on the basis of six soil variables provided three large distinct groups: swamp plots and non-swamp plots, the latter divided into plots of low and high available soil phosphorus. Swamp plots were distinguished by high abundances ofProtomegabaria stapfiana andLibrevillea klainei, though correspondence ordination of plots in these groups showedP. stapfiana associated with more clayey soils andLibrevillea klainei (andGluema ivorensis) on the very sandy soils. Direct gradient analysis highlighted several species associated with these lower phosphorus soils. Available soil phosphorus is not as low at Douala-Edea as in parts of Korup, and the association of these Douala-Edea soils with the Caesalpinioideae is correspondingly weaker.
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  • 51
    ISSN: 1432-2072
    Keywords: Blood-brain barrier ; Aluminum ; Dementia ; Peptides ; Phosphorus ; Acetylcholinesterase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of aluminum on levels of inorganic phosphorus and acetylcholinesterase in blood and brain and on permeability of the blood-brain barrier (BBB) in different regions of the brain to the neuropeptide deltasleep-inducing peptide (DSIP) was studied in adult rats. Aluminum (100 mg/kg) significantly increased the permeability of the BBB to intracarotid 125I-N-Tyr-DSIP so that levels of radioactivity in whole brain were 45% higher than in control animals. The pattern of regional distribution of radioactivity in the brain was, however, unaffected, demonstrating that the affect of aluminum occurs throughout the BBB. Aluminum also significantly decreased inorganic phosphorus levels in the serum by 19%, but this effect did not correlate with BBB permeability to DSIP. Aluminum did not decrease brain levels of phosphorus despite the drop in blood levels of phosphorus nor affect brain or blood levels of acetylcholinesterase. Experiments with radioactive 32P reinforced the finding that blood but not brain levels of phosphorus are reliably affected by aluminum. The lack of correlation between changes in BBB permeability and decreased levels of inorganic phosphorus in the blood suggests that the effect of aluminum may not be mediated by its effects on phosphorus metabolism. Also, the change in BBB permeability after administration of aluminum does not appear to depend on changes in brain cholinergic activity but does occur throughout the brain.
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  • 52
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    Environmental management 9 (1985), S. 243-251 
    ISSN: 1432-1009
    Keywords: Water quality ; Nitrogen ; Phosphorus ; Sedimentation ; 137Cs dating ; Freshwater lake ; Nutrient sinks ; Eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Nitrogen and phosphorus cycling in a eutrophic Louisiana freshwater lake system (Lac des Allemands) was studied. Nutrients from runoff entering the lake, as well as sediment-interstitial and lake water nitrogen and phosphorus fractions, were measured seasonally. Sedimentation rates in the lake were determined using137Cs dating. Phosphorus levels in the lake were found to be largely dependent on concentrations in the incoming bayou water from upland drainage. Lake water concentrations appear to respond to fluctuations in incoming waters. Laboratory equilibrium studies showed bottom sediments in the lake are a major sink for the incoming dissolved orthophosphate phosphorus. Total nitrogen concentrations in the lake water generally exceeded incoming runoff concentrations, suggesting fixation by the large blue-green algae population in the lake as being the major source of nitrogen to the system. Sedimentation ranged from 0.44 cm/year to 0.81 cm/year, depending on the proximity to the inlet bayous. Even though the lake is eutrophic the sediment served as a buffer by removing large amounts of carbon, nitrogen, and phosphorus through sedimentation processes. Carbon, nitrogen, and phosphorus were accumulating in the sediment at rates of 60, 7.1, and 1.1 g/m2/year, respectively. The water quality of the lake is likely to continue to decline unless measures are taken to reduce municipal, industrial, and agricultural inputs of phosphorus into the lake.
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  • 53
    ISSN: 1432-0789
    Keywords: Iron ; Phosphorus ; Siderophore ; Hydroxamate ; Chelates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Hydroxamate siderophores (HS) are microbially produced, ferric-specific chelates, known to occur in soil, and to be capable of providing iron to higher plants. This study examined the potential for HS to influence the diffusion of both iron and phosphorus to plant roots in soil. The HS desferrioxamine-B (DFOB) and desferriferrichrome (ferrichrome) were compared with the synthetic chelates ethylenediamine [di(o-hydroxyphenylacetic)acid] (EDDHA) and ethylenediamine-tetraacetic acid (EDTA), and citrate, oxalate, and distilled water in their ability to increase diffusion of iron using a simulated root technique. Chelate solutions were pumped through porous fiber bundles imbedded in soil previously labeled with55Fe. In a sandy loam of pH 7.5,55Fe diffusion caused by 10−4 M DFOB was twice that of water, but similar to that caused by 10−4 M EDDHA. However, 10−3 M EDDHA resulted in greater diffusion than 10-3 M DFOB. The diffusions resulting from equimolar quantities of citrate, oxalate, and EDTA were similar to that with distilled water. In a clay soil of pH 5.2 previously labeled with55Fe and32 P, the response in55Fe diffusion to chelate treatments was: 10−4 M EDDHA 〉 10−4 M ferrichrome 〉 10−3 M DFOB 〉 10−4 M DFOB 〉 water. Both ferrichrome and EDDHA caused2 P diffusion to increase substantially over that of distilled water. These results suggest that hydroxamate siderophores present in the rhizosphere could effectively increase the level of soluble iron for root uptake and possibly increase phosphorus uptake by solubilization of phosphorus from iron phosphates at acid pH.
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  • 54
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    Plant and soil 86 (1985), S. 27-34 
    ISSN: 1573-5036
    Keywords: Loblolly pine ; Nitrogen ; Nutrient ratios ; Phosphorus ; Pinus taeda
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Nitrogen and phosphorus limitations to growth are common in many loblolly pine (Pinus taeda) stands. Interactions of these nutrients may complicate interpretation of foliar nutrient analysis for predicting response to forest fertilization. Proportions of foliar nutrient concentrations (and the changes in these proportions following fertilization) were examined in 36 semi-mature loblolly pine plantations in the southeastern United States. Mean proportions of nutrient concentrations (N∶P∶K∶Ca∶Mg) for non-fertilized stands were 100∶9.3∶36.5∶17.2∶9.2. Potassium and phosphorus were higher. Nitrogen fertilization generally decreased the P∶N ratio and enhanced growth, indicating a nitrogen deficiency in most stands under study. Additions of nitrogen and phosphorus together yielded a significant increase in the P∶N ratio. Effects of fertilization effects on other nutrient concentration ratios were also examined.
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  • 55
    ISSN: 1573-5036
    Keywords: Eucalyptus marginata ; Lignotuber ; Nitrogen ; Phosphorus ; Seedlings ; Virgin soils X-ray probe microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Jarrah seedlings were grown in six virgin Western Australian soils for up to 27 months. Lignotubers were produced in all soils and formed 10–16% of plant dry weight. The phosphorus concentration in the lignotuber (250–800 μg g−1) was nearly twice that in the stem and roots. The lignotuber contained 10–30% of total plant phosphorus and like the leaves was a sink for phosphorus. In one lateritic soil the phosphorus concentrations of lignotuber and stem barks were similar. However, in the same plants the concentration of phosphorus in the lignotuber wood was five times the phosphorus concentration in stem wood. Hence both lignotuber bark and sap wood in young jarrah seedlings are storage sites for phosphorus. X-ray probe analysis showed that wood phosphorus was associated with the ray parenchyma. Unlike phosphorus, nitrogen did not accumulate in the lignotuber and the concentrations of nitrogen were similar for roots, lignotubers and stems.
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  • 56
    ISSN: 1573-5036
    Keywords: Copper ; Iron ; Magnesium ; Manganese ; Mineral nutrition ; Nutrient translocation ; Phosphorus ; Rice ; Varietal tolerance ; Zinc ; Zinc fertilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effects of four Zn levels on the electrochemical and chemical properties of the soil solution, and on the growth and mineral nutrition of two rice varieties (IR26 and IR34) differing in tolerance to Zn deficiency were studied in the greenhouse using Zn-deficient soils from two locations. A similar experiment was conducted in culture solution to check how Zn addition affects translocation of other nutrients. In both soil and culture solution, plant Zn concentrations alone was not enough to account for varietal tolerance to Zn deficiency. Comparison of nutrient to Zn and shoot to root ratios of nutrients was more useful in determining the possible mechanism of varietal tolerance. IR 34 appeared to tolerate the disorder due to its lower Zn requirement, more efficient Zn translocation and ability to maintain lower Fe/Zn, Cu/Zn, Mg/Zn and P/Zn ratios in the shoot than the more susceptible variety, IR26. This was shown to be due to decreased translocation of Fe, Mg and P to shoots and decreased absorption of Cu by the root in IR34 in culture solution studies. Adding Zn further reduces translocation or absorption of these nutrients and depending on the nutrient supply of the soil, could cause deficiencies or mineral imbalances, especially of Fe, Cu, and P. These observed varietal differences regarding Zn requirement and the interaction of Zn with absorption and translocation of plant nutrients necessitates revision of recommendations for Zn fertilization. There is an inevitable need for Zn application in severely Zn-deficient soils regardless of rice variety. But on marginally Zn-deficient soils especially those low in Fe, Cu, or P, Zn fertilization is not advisable when resistant rice varieties are used.
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  • 57
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    Plant and soil 88 (1985), S. 93-100 
    ISSN: 1573-5036
    Keywords: Aluminum ; Calcium ; Copper ; Glycine max ; Iron ; Magnesium ; Manganese ; Nitrogen ; Phosphorus ; Potassium ; Sorghum bicolor ; Triticum aestivum ; Zea Mays ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Information is limited on soil contamination of leaves from field-grown row crops, especially with respect to aluminum (Al) analyses. The objective of this study was to determine the influence of washing leaf samples with either deionized water or detergent solution on elemental analyses for several agronomic crop plants. The crop plants sampled were corn (Zea mays L.), soybean (Glycine max L. Merr.), grain sorghum (Sorghum bicolor L. Moench), and wheat (Triticum aestivum L.). The crops were grown on a range of soil types, soil pH values, and tillage practices. Samples of upper leaves and lower leaves were collected separately. The samples were either not washed, washed with deionized water, or washed with detergent solution. After drying, grinding, and digesting, the samples were analyzed for Al, nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu). For all crop plants and conditions studied, there was no effect on measured N, P, K, Ca, Mg, Mn, Zn, or Cu concentrations, but measured Al and Fe concentrations were influenced by washing. In general, washing had a greater effect on Al analyses than on Fe analyses. Soybean samples were most affected by washing, while wheat samples seemed to be least affected. The results reflected greater contamination of lower leaves than upper leaves. Decontamination procedures appear necessary prior to Al and Fe analyses of field-grown crop plants.
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  • 58
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    Plant and soil 88 (1985), S. 271-273 
    ISSN: 1573-5036
    Keywords: Ammonia assimilating enzymes ; Anabaena azollae ; Azolla ; Nitrogen ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A field experiment was conducted and studied the effect of nitrogen and phosphorus on ammonia assimilating enzymes of Azolla. Nitrogen and phosphorus at 30 and 60 kg/ha respectively were tested andAzolla pinnata was inoculated at 200 g/m2. The Azolla samples were drawn on 24th hr, 7th day and 14th day and the ammonia assimilating enzymes glutamine synthetase (GS), glutamate synthase (GOGAT) and glutamine dehydrogenase (GDH) were estimated. Nitrogen and phosphorus have markedly suppressed the GDH activity but fertilizer nitrogen has no significant influence in inhibiting the enzyme activity of GOGAT and GS. In general phosphorus application also has stimulated the GS activity significantly during the first sampling period of 24th hour.
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  • 59
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    Plant and soil 89 (1985), S. 285-299 
    ISSN: 1573-5036
    Keywords: Calcium ; Chloride ; Ion antagonism ; Magnesium ; Nitrate ; Nitrogen ; Nutrition disorders ; Phosphorus ; Salinity-fertility relationship ; Sodium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Available data concerning nutrition and fertilization effects on crops irrigated with saline water are presented and discussed. Published data on the salinity-fertility relationship are, at least to some extent, contradictory; both positive and negative effects as well as no effect of fertilization on salinity tolerance have been recorded. However, a great deal of the experimental work supports the view that standard fertilization recommendations for non-saline conditions are also suitable for saline conditions. In addition, available data indicate that the apparent salt tolerance of agricultural crops varies with soil fertility level. Consequently, crops showing exceptionally high apparent salt tolerance at a low fertility level become more sensitive when adequately fertilized, although the absolute yield may be greatly increased. On the other hand, some data seem to show a real increase in salinity tolerance under improved fertility conditions. Important information concerning the responses of plants to salinity under various fertility levels was obtained by tissue analysis. It should be kept in mind that this information may be influenced also by the plant species and by environmental conditions.
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  • 60
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    Plant and soil 84 (1985), S. 269-273 
    ISSN: 1573-5036
    Keywords: Calcium ; Copper ; Groundnut ; Iron ; Kernel ; Kharif ; Leaflet ; Magnesium ; Manganese ; Nitrogen ; Petiole ; Phosphorus ; Potassium ; Root ; Shell ; Stem ; Sulphur ; Summer ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Concentration of N, P, K, Ca, Mg and S in summer groundnut crop was higher than in kharif while Zn, Fe, Mn and Cu contents were higher in summer crop. Kernel's N, P and Zn; Leaflet's Ca and Mn; Stem's K and Fe; Root's S and Cu and Petiole's Mg contents were highest. Shell's N, P, K, Mg, S, Zn and Cu; Kernel's Ca, Fe and Mn contents were the least. N, P, K, S, Zn and Cu concentrations decreased linearly as the crop grew. Ca, Mg, Fe and Mn concentrations did not display any distinct pattern. Ca concentration was positively correlated with pod yield in both the seasons.
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  • 61
    ISSN: 1573-5036
    Keywords: Cecil soil type ; Phosphorus ; Pinus taeda ; Scleroderma aurantium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A greenhouse study was conducted to evaluate the effect of ectomycorrhizae on loblolly pine (Pinus taeda L.) growing in a Piedmont soil. Pine seedlings were inoculated with one of four species of fungi (Scleroderma aurantium, Pisolithus tinctorius, Thelophora terrestris, andRhizopogon roseolus). The seedlings were grown in pots containing a Cecil sandy clay loam amended to create a gradient of extractable P ranging from 5.9 to 52.5 μg/g. After ten months, all colonized seedlings were significantly larger than control seedlings. However, of the four fungi,Scleroderma aurantium mediated a far superior shoot growth response to increasing levels of soil P; the seedlings were significantly larger than those colonized by any other fungus and also had the largest root systems and greatest degree of mycorrhizal colonization.
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  • 62
    ISSN: 0570-0833
    Keywords: Tetradentate ligands ; P ligands ; Arsenic ligands ; Phosphorus ; Arsenic ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of ligand shape on coordination numbers and geometry of coordination compounds has been studied using two tetradentate ligands containing phosphorus and arsenic. These tend to form five-coordinate complexes with trigonal bipyramidal structure [Fe(II), Co(I), Co(II), Rh(I), Ni(II), Pd(II), Pt(II)], but can also form six-coordinate complexes with octahedral structure [Fe(II), Ru(II), Os(II), Co(III), Rh(III), Pd(IV), Pt(IV)]. The magnetic properties and the stereochemistry of the complexes are explained by ligand field theory which predicts that, for metal ions with d6-electronic configuration, a low overall field strength should favor the formation of five-coordinate paramagnetic complexes while a high overall field strength should favor the formation of six-coordinate diamagnetic complexes. - This work provides further indication that the tendency of polydentate ligands to use all the potential donor atoms is not as pronounced as is generally believed. This is shown by the isolation of chromium(III) complexes in which the tetradentate ligands are, in fact, acting as tridentate, and by the isolation of mercury(II) complexes where only two of the four donor atoms of the polydentate ligand are actually bonded to the central metal atom.
    Additional Material: 9 Ill.
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  • 63
    ISSN: 0570-0833
    Keywords: Stereospecific polymerization ; Polymerization ; Polycyclopentene ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of cyclo-olefins, like that of olefins with an internal double bond, is sterically hindered. Within recent years it has become possible to prepare copolymers of these compounds with ethylene, with the aid of anionic coordination Ziegler catalysts. This copolymerization always results in cis-opening of the double bond. Despite the steric hindrance, cyclobutene and cyclopropene have also been homopolymerized, with opening of the double bond. - Rather surprisingly, the best catalysts for homopolymerization of cyclopentene are those which exhibit low activity in the polymerization of ethylene. Ring cleavage occurs with MoCl5/Al(C2H5)3 to give the cis-polypentenamer, whereas WCl6/Al(C2H5)3 gives the trans-polypentenamer. Both polypentenamers exhibit elastomeric properties. - Evidence from infrared spectra and oxidative degradation indicates that the monomer units in the trans-polypentenamer are linked head-to-tail. It is presumably the single bond adjacent to the double bond that is broken. Using X-ray methods at -50 °C, it was possible to determine the crystal structure of the crystalline trans-polypentenamer at about 400% elongation.
    Additional Material: 6 Ill.
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  • 64
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 523-530 
    ISSN: 0570-0833
    Keywords: Semimetals ; Metallic structure ; Nonmetallic structure ; Antimony ; Arsenic ; Bismuth ; Phosphorus ; Tellurium ; Tin ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Measurements on semimetals have been continued. Studies of the dependence on temperature of various properties have provided details regarding the transition from the nonmetallic to the more metallic structure. A second-order transition has been found for tin at 170 °C, in which the c-axis remains unchanged, while the a-axis undergoes a small, discontinuous elongation.
    Additional Material: 13 Ill.
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  • 65
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 704-714 
    ISSN: 0570-0833
    Keywords: Titanium ; Alkenes ; Polymerization ; Titanium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: At low temperatures, ethylene and α-olefins (Δ1-olefins or 1-alkenes) are rapidly converted into oligomrs by the two-component organometallic catalyst CH3TiCl3·CH3AlCl2. To achieve smooth oligomerizations, aromatic or chlorinated hydrocarbons must be used as solvents. Although the activity of the titanium-carbon bond is enhanced by the aluminum component of the catalyst, the aluminum and its methyl group do not participate in the reaction proper; the latter proceeds exclusively at the titanium-carbon bond. The reaction will olefins can be used as an analytical method for the quantitative determination of the titanium-carbon bond in admixture with the organoaluminum component. It is thus possible to follow the reaction leading to formation of the catalyst from titanium tertrachloride, as well as the processes occurring at the titanium-carbon bond during the oligomerization of olefins. All the observations indicate that the catalyst possesses an ionic structure which is determined by the solvent. It is shown that the initial reaction step probably involves formation of a complex between the olefin and the alkyltitanium cation. The reaction scheme proposed is based on organometallic reactions which are characterized by carbanion and hydride transfers within the olefin-cation complex. This mechanism, which is unusual for Ziegler catalysts, is due to the predominance of hydride transfers.
    Additional Material: 2 Ill.
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  • 66
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 646-654 
    ISSN: 0570-0833
    Keywords: Polyphosphanes ; Phosphanes ; Phosphorus ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: While silicon and sulfur, which are situated to the left and to the right of phosphorus in the periodic table, from numerous chain and cyclic Si-Si and S-S-compounds with varying numbers of members, until recently the polyphosphance chemistry has been limited to the two-membered compounds diphosphane P2H4 and its derivatives. A number of results obtained in studies on polyphosphanes carried out in recent years will therefore be discussed, which, together with some more recent work by other authors, have led to an expansion of our knowledge of the prepration and properties of straight and branched-chain as well as of cyclic and polycylic -P-P-systems.
    Type of Medium: Electronic Resource
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  • 67
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 32-41 
    ISSN: 0570-0833
    Keywords: Polymerization ; Polyethylene ; Titanium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A two-component organometallic catalyst of composition CH3TiCl3·CH3AlCl2 effects high-speed polymerization of ethylene in the presence of chlorinated hydrocarbons at low temperatures. The catalyst does not undergo any alteration in the process. In contrast to the Ziegler catalysts, the titanium remains quadrivalent. Olefins of low-molecular-weight and with branched structures are produced. It proved possible to isolate the primary products of the polymerization at -50 to -100°C and to elucidate the mode of their formation from a knowledge of their structures. The findings are incompatible with either a cationic or anionic reaction mechanism. A novel type of mechanism is proposed, whereby the catalyst is supposed to have an ionic structure and molecular growth proceeds via π-complex formation of the olefin with the titanium cation. The formation of ethylene/olefin copolymers is also discussed.
    Additional Material: 1 Ill.
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  • 68
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 295-308 
    ISSN: 0570-0833
    Keywords: Emulsion polymerization ; Polymerization ; Polymerization ; Alkenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ionizing radiation induces the polymerization of some vinyl monomers in aqueous emulsion with high radiation yields. With identical emulsion compositions, the kinetics of this reaction and the kinetics of emulsion polymerization induced by water-soluble initiators are very similar. The rate of reaction in emulsion polymerization is about one hundred times greater than in bulk polymerization. The initiation of emulsion polymerization by means of ionizing radiation permits uniform “illumination” of the reacting volume, as well as almost any desired variation in the frequency of initiation during the reaction. The sharp decrease in the overall rate of reaction when initiation is interrupted during emulsion polymerization of styrene induced by γ-rays contradicts the earlier concept of sharply separated reaction zones.
    Additional Material: 11 Ill.
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  • 69
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 617-621 
    ISSN: 0570-0833
    Keywords: Isocyanates ; Phosphorus ; Silicon ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several aminoaryl esters of phosphoric and thiophosphoric acids were prepared by the reaction of phosphorus pentahalides with nitrophenols, followed by catalytic hydrogenation, or by treating aminophenols with phosphorus trihalides and oxidation to pentavalent phosphorus. These amino esters were then converted into isocyanato esters by the action of phosgene. Isocyanates of phosphonates have been synthetized on the same principle, as well as via the Arbusov reaction of halogen-substituted isocyanates with trialkyl phosphites. The reaction of silicon halides or alkylhalogenosilanes with aminophenols yielded aminoaryl esters of silicic acid or its derivatives, which could also be treated with phosgene to convert them into isocyanato esters.
    Type of Medium: Electronic Resource
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  • 70
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 652-656 
    ISSN: 0570-0833
    Keywords: β-Chloroethanephosphonic dichloride ; Phosphorus ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ethylene, phosphorus trichloride, and oxygen react together to give β-chloroethylphosphonic dichloride in good yields. Being a bifunctional acid chloride, this compound undergoes polycondensation reactions with other, at least bifunctional, compounds affording polyesters, polyamides, epoxy resins, etc. β-Chloroethylphosphonic dichloride also may be converted into vinylphosphonic dichloride, thus serving as a starting material for the preparation of vinylphosphonic acid and its derivatives. These undergo both homopolymerization and copolymerization with compounds containing olefinic double bonds. The products are used in the field of synthetic resins, for dressing textiles, and as protective surface coatings.
    Additional Material: 1 Tab.
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  • 71
    ISSN: 0570-0833
    Keywords: Pyrrolidone ; Polyamides ; Fibers ; Lactams ; Polymerization ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The industrial production of capryllactam (1-azacyclononan-2-one) and of laurolactam (1-azacyclotridecan-2-one) starts with cyclization of acetylene or butadeine to give cyclooctatetraene or cyclooctadiene, or cyclization of butadiene to give cyclododecatriene. Further steps are: oxidation of the cyclic hydrocarbon to the ketone, formation of the oxime, and rearrangement of the latter with sulfuric acid. Pyrrolidone can be prepared from acetylene and formaldehyde by way of butyrolactone. The behavior of the lactams during polycondensation is described and the properties of the resulting fibers are compared with those of the known polyamide fibers.
    Additional Material: 2 Ill.
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  • 72
    ISSN: 0570-0833
    Keywords: Lactams ; Polymerization ; Fibers ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: β-Lactams can be prepared by cyclization of β-aimno acid esters. Recently they have become available also from olefins by addition of N-carbonysulfamyl chloride (isocyanatosulfonyl chloride) and from aldehydes by reaction with N-carbonylsulfamyl chloride and ketene. Condensative or anionic polymerization results in polyamides the chains of which contain many more amide groups than the chains of polyamides of the nylon-6 type. Hence the new polymers resemble silk moreclosely. Fibers and films can be prepared from solution.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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