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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 27 (1979), S. 19-26 
    ISSN: 1432-0827
    Keywords: Bone diseases ; Familial hypophosphatemia ; Magnesium ; Mice ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A new genetic mutant in mice,Hyp, has been proposed as a model for the human disease X-linked hypophosphatemia (the most common form of vitamin D-resistant rickets). The gene is X-linked, dominant, and produces reduced renal tubular reabsorption of phosphate, hypophosphatemia, and dwarfism. Our goal was to evaluate the skeletal changes histologically and to measure chemically the prominant blood and bone minerals to judge the suitability of this mutant as a model for the human disease. Thirteen-week-old hemizygousHyp male mice were compared with their normal littermate controls. TheHyp mice were hypocalcemic, hypophosphatemic, hypermagnesemic, and had elevated plasma alkaline phosphatase. The femur ash weighed less than half the normal ash weight but had a normal Ca:P ratio. The ash composition was high in %Na and K but low in %Mg. The mandibular incisor ash was also low in %Mg. Histologically the femur showed wide osteoid borders and wide epiphyseal plate. Microradiography revealed reduced bone density and enlarged osteocyte lacunae. Skeletal muscle samples, although smaller in theHyp mice, showed no striking alternations in inorganic or total phosphate content, dry weight (as % wet weight), or extracellular fluid space. TheHyp gene in mice seems to produce a condition similar to that of X-linked hypophosphatemia in humans.
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  • 2
    ISSN: 1573-5117
    Keywords: Fertilizer ; Nutrients ; Soluble Phosphate ; Equilibrium Phosphate Concentration ; Phosphorus ; Pond ; Sediment ; Erosion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We chose two surface soils with contrasting textures as model sediments for a model pond study. One soil, a calcareous clay, had a relatively high natural phosphate content and a large phosphate adsorption capacity. The second soil, a non calcareous loam, had a relatively low natural phosphate content and a small phosphate adsorption capacity. Chemical characteristics of both soils were roughly proportional to mineral surface area. Pasture sites of each soil were tilled to a depth of 15 cm and two plots at each site were fertilized by hand with triple superphosphate. A third plot at each site was left unfertilized. After fertilization the plots were mechanically mixed and left fallow for 2 to 3 months. Then the plots were resampled and equilibration phosphate concentrations were determined again. Results showed significant phosphate fixation by the clay soil but no fixation by the loam soil.
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  • 3
    ISSN: 1573-5117
    Keywords: Phosphorus ; herbicide ; diquat ; nutrient cycling ; sediment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phosphorus (P) concentrations in water and sediment of a highly eutrophic lake were monitored before and after application of diquat to control the macrophyte Potamogeton crispus. Only a relatively small and short-term increase in P concentration in water occurred shortly after plant die-off resulting from herbicide application. Phosphorus concentrations in shallow water sediments decreased during the summer, and those in deep water sediments increased. Although a large increase in P concentration in the water occurred in late summer, it was not attributed to diquat. No major secondary effects of herbicide application were found during this study.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 51 (1979), S. 331-340 
    ISSN: 1573-5036
    Keywords: Deficiency ; Distribution ; Fruit ; Glasshouse ; Laminae ; Leaves ; Nitrogen ; Peat ; Petioles ; Phosphorus ; Plant ; Superphosphate ; Symptoms ; Tomato ; Uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The uptake and distribution of phosphorus was examined in tomato plants, cv. Kirdford Cross, grown in peat to which phosphate was added (P2) or omitted (P1). The plants received a liquid feed containing either a high (N2) or low (N1) concentration of ammonium nitrate. Initially, all plants were grown in peat containing an intermediate level of phosphate. There was a rapid net export of P from the leaves of plants transferred to the P1 medium resulting in deficiency symptoms before the fruit on the first truss had ripened. Most of the P absorbed by 11-week-old plants in the N1P2 and N2P2 treatments was located in the developing fruit, in the laminae of the mature leaves and in the lower parts of the stem. In the P1 treatments, the lowest fruit truss was the dominant sink for the limited supply of P, but there was also a significant concentration of P in the shoot apex and in the laminae. Increasing the supply of N to plants in the P2 treatment promoted the transport of P to the shoot and to the fruit trusses and also increased the total P uptake. However, plants in the N2 treatment required a significantly higher level of tissue P to prevent the symptoms of P deficiency occurring in the laminae. Generally, symptoms occurred in laminae of mature leaves containing less than 0.13 per cent P. Increases in concentration of tissue P in response to raising the level of applied P were greatest in the petioles of the mature leaves, and it is suggested that these petioles are the most suitable tissues for the assessment of the P status of tomato plants.
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  • 5
    ISSN: 1573-5036
    Keywords: Alluvial soil ; Alternate waterlogged and saturated ; Copper ; Immobilization ; Interaction ; Iron ; Manganese ; Organic matter ; Phosphorus ; Reduction ; Rice ; Saturated ; Waterlogged ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A laboratory incubation experiment was conducted to study the influence of three moisture regimes,viz (i) waterlogged (W1), (ii) alternate waterlogged and saturated (W2) and (iii) continuous saturated (W3) and two levels of organic matter application,viz (i) 0 (T1) and (ii) 0.5% of the soil (T2) in their all possible combinations on the extractable (N NH4OAC, pH 7.0) zinc and copper in three lowland alluvial rice-growing soils of West Bengal (India). The results showed that the extractable zinc and copper content in soils recorded marked decrease on incubation under all the moisture regimes, but the same was most prominent under the continuous saturated moisture regime (W3), followed by waterlogged (W1) and alternate waterlogged and saturated (W2) moisture regimes. Application of organic matter brought about further decrease in the content of these elements. Organic matter application combined with saturated moisture regime brought about the greatest decrease both in zinc and copper content. The microbiological immobilisation and the antagonistic effect of increased concentration of extractable iron, manganese and phosphorus have been suggested as the possible reasons for the observed decrease of the content of extractable zinc and copper.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 51 (1979), S. 247-256 
    ISSN: 1573-5036
    Keywords: Nutrient distribution ; Phosphorus ; Tropical legumes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Changes in absolute contents of nutrient elements of old leaves of two tropical pasture legumes were studied during vegetative growth in order to determine the extent of nutrient reutilization. Over a wide range of P supply, the P contents of old leaves ofDesmodium intortum cv. Greenleaf generally increased slightly with time whereas inMacroptilium atropurpureum cv. Siratro they decreased. In both species, relatively less K than P was retained in old leaves, especially in plants grown at high P supply. In desmodium, contents of N, S, Ca, Mg, B, Zn and Mn in old leaves generally increased with plant age. In Siratro, S content of old leaves decreased, but to a lesser extent than P content, and contents of N, Ca, Mg, B, Zn and Mn either changed little or increased with plant age. The lower net loss of elements from old leaves of desmodium than Siratro was associated with a greater increase over time in dry weight of old desmodium leaves. The losses of elements other than K from old leaves of Siratro and desmodium with time were relatively smaller than those reported for other species. This suggests that these legumes survive restricted supply of such elements from the roots by reducing their growth rather than by reutilizing nutrients in old leaves. By contrast, these plants can continue to grow when K supply from the roots slows or ceases by utilizing K in old tissues for growth of young tissues.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 51 (1979), S. 341-353 
    ISSN: 1573-5036
    Keywords: Fruit development ; Glasshouse ; Growth ; Nitrogen ; Peat ; Phosphorus ; Protein ; Sand ; Tomato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effect of P nutrition on the growth of tomato plants in peat was examined. Initially, plants received an adequate supply of P and then received either nil, 0.78 or 2.34 kg superphosphate per m3 in combination with either 50 μg N/ml (N1) or 300 μg N/ml (N2) as ammonium nitrate in a liquid feed. Vegetative growth was restricted in the lower P treatmentsi.e. inhibited shoot growth, reduced duration of leaf expansion phase, thinner stems and reduced vegetative dry wt. Plants receiving N2 showed a greater restriction in growth compared with N1 plants when the P supply was limiting. P deficiency disrupted protein metabolism in the leaves, in that soluble leaf protein was reduced and trichloroacetic acid-soluble N accumulated. Flower development was accelerated by low P applications but the final numbers of flowers and the fruit-setting efficiency were reduced. Lowering the N supply reduced the fruit yield by 36 per cent while an intermediate P level reduced yields by about 15 per cent. Maximum fruit yields and good vegetative growth occurred when plants contained 0.4 per cent P or above in the mature leaves, and this value was achieved by adding the highest level (2.34 kg/m3) of superphosphate to the peat.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 51 (1979), S. 485-490 
    ISSN: 1573-5036
    Keywords: Crude protein ; Fodder ; Nitrogen ; N/S ratio ; Phosphorus ; Protein ; Raya ; Selenium ; S-amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effects of Se and P on the dry matter yield and chemical composition of Raya (Brassica juncea Cos. var. R.L. 18) were studied in the green-house. The dry matter yield in P treated and untreated pots increased with Se application upto 2.5 ppm. With further increase in Se dose upto 10 ppm, dry matter yield decreased. The increase in P dose from 0 to 50 ppm increased dry matter yield in all Se treated and untreated pots but 100 ppm P rather showed decrease in dry matter yield as compared to 50 ppm P. The Se concentration increased by about 100 fold with the application of 10 ppm Se over 0 ppm Se where P was not added whereas increase was 258 and 336 times when 50 ppm and 100 ppm P was added, respectively. Inorganic, organic and total P increased with increasing Se and P. The increase in inorganic P was more than organic and total P. S and N concentration decreased with increasing Se application and increased with P application. Crude protein showed the same behaviour as N. The total sulphur-containing amino acids (which ranged from 39 to 49% of crude protein) and individual sulphur-containing amino acids like methionine (16.9 tot 20%) cysteine (9.8 to 13%) and cystine (12.3 to 15.9%) decreased with the increasing selenium but increased with increasing phosphorus. N/S ratio in the plant showed significant negative correlation with total sulphur-containing amino acids (r=−0.940**), methionine (r=−0.951**), cysteine (r=−0.929**) and cystine (r=−0.920*) whereas total sulphur in the plant showed positive significant correlation with methionine (r=0.805**), cysteine (r=0.924**) and cystine (r=0.821**).
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 51 (1979), S. 551-561 
    ISSN: 1573-5036
    Keywords: Autoradiography ; Culture solution ; Fe deficiency ; Millet ; P/Fe interaction ; Phosphorus ; Sorghum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Seedlings of millet (Pennisetum americanum (L) K. Schum var. Tift 23 DA × Tift 18 DB) and guineacorn (Sorghum bicolor (L) Moench var. RS' 702) were employed in growth chamber studies to evaluate the effects of various phosphorus (P) levels on their growth and nutrient composition. The growth medium was Hoagland solution containing 0.0, 0.1, 1.0 and 2.5 mM P and 2.2 mM ferrous sulphate-tartate solution. At the end of twenty-four days, two plants from each treatment were supplied with 0.31 μci/ml of radioactive iron (55Fe) (with the same P levels used to grow them) and then allowed to absorb the55Fe for 3 hours after which they were harvested, separated into roots and shoots. The two components were wet-ashed separately, and assayed for55Fe. The rest of the plants in Hoagland solution were also harvested, separately into roots and shoots. The components parts were also wet-ashed separately and assayed for iron (Fe), manganese (Mn), zinc (Zn), copper (Cu) and phosphorous (P). High P concentration in the growth medium inhibited55Fe absorption and translocation in both millet and sorghum but millet was more tolerant of P-induced Fe deficiency than sorghum. Millet and sorghum grew best at 1.0 and 0.1 mM P, respectively. Fe concentrations in plant declined as P levels increased; while Mn increased in both millet and sorghum with increasing P levels. Millet, however, maintained higher concentrations of Fe and Mn. The distribution patter of55Fe, regardless of P levels could be summarized as follows: Roots〉Vascular tissue〉leaf-sheaths〉leaf blade. Less55Fe was absorbed and translocated to shoots at 2.5 mM P, in millet and sorghum.
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  • 10
    ISSN: 1573-5036
    Keywords: Gaeumannomyces ; Phialophora ; Phosphorus ; Potassium ; Water use ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The water consumption and levels of phosphorus, potassium, and total minerals were measured for wheat seedlings colonized byGaeumannomyces graminis var.tritici, Phialophora radicicola var.radicicola, orPhialophora radicicola var.graminicola. Infection byG. graminis resulted in a considerable reduction in water consumption, and reduced level of phosphorus when the supply of phosphorus to the seedlings was plentiful. Colonization byP. radicicola var.radicicola increased levels of phosphorus and potassium, but these increases varied according to the isolate of the fungus and the supply of phosphorus and potassium available to the seedlings. Colonization byP. radicicola var.graminicola resulted in reduced water consumption by the seedlings. The results are discussed in relation to stelar cell wall thickening in wheat roots colonized byP. radicicola, and the effects on nutrient uptake of mycorrhizal root systems.
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  • 11
    ISSN: 1573-5036
    Keywords: Foliar fertilization ; Growth ; Leaf area ; Mineral composition ; Peanut ; Phosphorus ; Sand culture ; Stomatal frequency ; Yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Peanut (Arachis hypogaea L., Var. TMV-2) plants were raised in sand cultures under natural photoperiod. Salt treatment (0.4% NaCl on dry weight basis) was given 10 days after sowing. Nutrient solution was supplied 15 days after sowing to control and salinized plants. Phosphate (0.1% NaH2PO4 with 0.01% Tween-80) was sprayed to the plants to the drip point once daily from 20th to 25th day and from 30th to 35th day. The plants were harvested at 30th and 40th day for analysis. The plants grown under saline conditions showed a market reduction in growth. When phosphorus was supplied to saline plants by foliar application, there was an increase in dry weight, leaf area, stomatal frequency, and yield and the increase was more marked when the plants received phosphate for two periods. Phosphorus content decreased due to salinity which was restored by foliar spray of phosphate. With salinity, sodium accumulated while potassium and calcium were lowered. Phosphate spray decreased sodium and increased potassium and calcium in general.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 52 (1979), S. 139-149 
    ISSN: 1573-5036
    Keywords: Algal growth ; Iron ; Manganese ; Phosphorus ; Rice soils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Laboratory experiments were conducted to study the effect of algal growth on the change of (I) pH, (II) available phosphorus and (III) solubility of iron and manganese content in five waterlogged alluvial rice soils of West Bengal, India. The results showed that the algal growth initially caused an increase in the soil pH, which later declined to the original value in some of the soils. The available phosphorus content decreased upto 90 days of their growth and began to increase towards the later period of incubation. The drastic fall of water soluble plus exchaneable manganese content of the soils due to algal growth was accompanied by similar increase in reducible manganese content. No appreciable change in water soluble plus exchangeable ferrous iron content was encountered but theN-NH4OAC(pH 3) extractable iron due to algal growth progressively decreased with the progress of the incubation period.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 12 (1979), S. 212-214 
    ISSN: 1612-1112
    Keywords: Phosphorus ; Chromatography, gas-liquid ; Alloys, copper
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple, sensitive, accurate and rapid gas chromatographic method for the quantitative determination of phosphorus in copper-phosphorus alloys is described. The method is based on the chlorination of the sample with carbon tetrachloride in a sealed glass capsule at 550°C. The volatile products are introduced into the gas chromatograph after crushing the capsule in a special device. The method is very quick (ca. 20 min), involves simple manipulations and the error is about ±0.5%.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 57 (1978), S. 209-215 
    ISSN: 1573-5117
    Keywords: Phosphorus ; growth rate ; phytoplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Laboratory experiments with natural phytoplankton assemblages from three lakes (two mesotrophic and one oligotrophic) showed that added PO4 predictably affected growth rate (µ, determined as P : B) while NO3 had little effect even when the N P ratio approached one. The response to PO4 followed the typical Monod-type function. The lack of effect of NO3 on µ at such low N : P ratios is in striking contrast to the added effect of NO3 Plus PO4 on maximum biomass produced versus only PO4 alone.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 59 (1978), S. 151-154 
    ISSN: 1573-5117
    Keywords: Remineralization ; Phosphorus ; SRP ; Freshwater Zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During a six-month study at Lake George, N.Y., zooplankton contributed an average of 19.4% of the phosphate required for algal photosynthesis. Values ranged from 44.1% prior to the unimodal phytoplankton pulse to 4.6% during the phytoplankton bloom. Copepods accounted for a large percentage (21–68%) of the SRP recycled during the growing season examined, whereas, the cladocera provided only a small percentage of remineralization (6.9%).
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  • 16
    ISSN: 1573-5117
    Keywords: Phytoplankton ; Eutrophication ; Ordination analysis ; Diatoms ; Nutrient enrichment ; Phosphorus ; Laurentian Great Lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A natural phytoplankton assemblage from Grand Traverse Bay, Lake Michigan, was treated with factorial enrichments of nitrate and phosphorus, with maintained nutrient concentrations ranging from 5 to 60 µg total soluble phosphorus liter−1 and 0.225 to 1.12 mg nitrate-nitrogen liter−1.One container was spiked with added vitamins, a chelator, and trace metals. The assemblage response was monitored at the species level. Significant differences in growth rates as a function of nutrient enrichment were detected at both the division and the species levels. Growth rates associated with the various levels of enrichment are reported for several diatom taxa. Many of the diatom taxa exhibited highly significant (P 〈 0.01) increases in growth rate after phosphorus enrichment, with the largest effects occurring between 5 and 15 µg total soluble phosphorus liter−1. Significant (P 〈 0.05) N effects were also observed, and the nature of these effects was found to be taxon-specific. Taxa also showed significant changes in percent composition, due both to time and to nutrient enrichment, indicating a substantial heterogeneity in response at the species level. Experimentally induced population changes were qualitatively similar to those observed in regions of the Great Lakes which have undergone anthropogenic eutrophication.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 22 (1977), S. 9-17 
    ISSN: 1432-0827
    Keywords: Bone ; Fluoride ; Calcium ; Phosphorus ; Mechanical Strength
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Four groups of weanling rats were fed for 2 weeks on a diet sufficient or insufficient in calcium and/or phosphorus. Each group was divided into four subgroups which were offered distilled water supplemented with 0, 50, 75, or 150 ppm fluoride. High levels of fluoride in drinking water inhibited weight gain. This inhibition was less in rats deficient in phosphorus than when normal-phosphorus diets were offered. At a low level, fluoride was without any effect on bone ash, thickness of femoral cortical bone, and mechanical strength, as measured by maximal load, ultimate stress to breaking, and limit of elasticity. Modulus of elasticity was decreased. At higher levels fluoride tended to decrease most of these parameters, except in rats deprived of both calcium and phosphorus. The effect of fluoride was modified by lack of dietary calcium and/or phosphorus and appeared to be weaker in rats deficient in these nutrients. Lack of dietary calcium and/or phosphorus decreased bone strength more than did fluoride content of water and of bone mineral. Concentration of bone ash and thickness of femoral cortical bone were closely correlated with parameters of mechanical strength.
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  • 18
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    Electronic Resource
    Springer
    Calcified tissue international 23 (1977), S. 121-124 
    ISSN: 1432-0827
    Keywords: Vitamin D ; Metabolic acidosis ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The metabolism of vitamin D3 was studied in 3-week-old, vitamin D deficient chicks, fed since hatching with a diet containing 3% ammonium chloride, 1% calcium, and 0.7% phosphorus. When kidney homogenates were incubated in vitro with [3H]25-(OH)D3, the production of 1,25-(OH)2D3 was reduced by 40% in acidotic birds. During in vivo experiments, after injection of [3H]D3 (1220 pM/bird), the level of 1,25-(OH)2D3 was also reduced in blood plasma, intestine, and tibiae in acidotic chicks as compared with the controls. As a large increase in plasma phosphate was found during acidosis, these results are discussed in relation to the possible role of phosphorus in the control of 1,25-(OH)2D3 synthesis.
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  • 19
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    Springer
    Skeletal radiology 1 (1977), S. 191-208 
    ISSN: 1432-2161
    Keywords: Vitamin D ; Rickets ; Osteomalacia ; Parathyroid hormone ; Skeleton ; Calcium ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Major advances in the field of vitamin D metabolism have been achieved in the past decade that have considerably enhanced our understanding of a variety of metabolic bone diseases which include the rachitic and osteomalacic syndromes and parathyroid gland disorders. Delineation of the biochemical structure, metabolic pathways, mechanisms regulating synthesis, and physiologic functions has established that the compound should more appropriately be considered a hormone. Obligatory sequential, two-step hydroxylation of the prohormone, vitamin D, is necessary before physiologic action occurs. Initial hydroxylation occurs mainly in the liver while the second hydroxylation occurs exclusively in the kidney. The physiologically active form of the hormone, 1,25-(OH)2-D, coordinates with parathyroid hormone (and probably calcitonin) in promoting homeostasis of both extra-cellular calcium and phosphorus and the skeletal system. This article reviews the basic metabolism of vitamin D, the modes of physiologic action, the endocrine features of vitamin D and its relationship to parathyroid hormone, and discusses the important medical applications of this information.
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  • 20
    ISSN: 0570-0833
    Keywords: Phosphorus ylides ; Ylides ; Phosphorus ylides ; Synthetic methods ; Phosphorus ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phosphacumulene ylides and phosphaallene ylides are nucleophilic compounds which can add reactants in a variety of ways. Cycloadditions can occur both at the polar C - P ylide bond and at the C=C double bond.
    Additional Material: 13 Tab.
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  • 21
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    Electronic Resource
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    Hydrobiologia 50 (1976), S. 11-15 
    ISSN: 1573-5117
    Keywords: Phosphorus ; zooplankton excretion ; characterization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The characteristics of phosphorus excretions of zooplankton collected in spring 1974 from Stonehouse Pond, New Hampshire were studied with gel filtration, ultraviolet spectroscopy and seston incorporation. The soluble phosphorus component released from a natural population has a molecular weight the same as orthophosphate and behaves similar to orthophosphate in seston incorporation studies. Approximately 15 percent of the total phosphorus released was organic, but could not be identified by ultraviolet spectroscopy. No evidence of nucleic acid excretion or any hydrolytic degradation product was detected in the ultraviolet spectrum.
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  • 22
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 14 (1975), S. 232-245 
    ISSN: 0570-0833
    Keywords: Antimony ; Arsenic ; Bismuth ; Boron ; Germanium ; Phosphorus ; Silicon ; Bond theory ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Recent years have seen the preparation of π systems containing novel (p-p)π bonds between carbon and elements from the third, fourth, and fifth Main Groups of the Periodic Table; most of these compounds are predicted to be incapable of existence according to the classical concepts of the double bond. (p-p)π. Bonds between carbon and phosphorus, arsenic, and antimony have been successfully stabilized in resonance-stabilized colored compounds of the cyanine and triphenylmethane type, and also in aromatic systems deriving from benzene, naphthalene, and anthracene. Bismuth-carbon and boron-carbon (p-p)π bonds have likewise been confirmed in aromatic systems. Silicon-carbon and germanium-carbon (p-p)π bonds have been detected in extremely reactive derivatives of silaethylene and germaethylene, respectively. The present report describes characteristic reactions of the new π systems. Their bonding follows from X-ray structure analysis, from photoelectron, UV, and NMR spectra, and from calculations. Criteria for the existence of π systems which are not allowed by the classical double bond rule are discussed; these criteria remain valid on generalization.
    Additional Material: 6 Ill.
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  • 23
    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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  • 24
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    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.
    Type of Medium: Electronic Resource
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  • 25
    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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  • 26
    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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  • 27
    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.
    Type of Medium: Electronic Resource
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