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  • 2000-2004  (11)
  • 1965-1969  (12)
  • 1960-1964  (13)
  • 1920-1924
  • Fibers
  • Phosphorus
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 32 (2000), S. 328-339 
    ISSN: 1432-0789
    Keywords: Key words Biomass transfer ; Maize ; Phosphorus ; Resin extractable phosphorus ; Triple superphosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  The effects of organic residues and inorganic fertilizers on P availability and maize yield were compared in a Nitisol of western Kenya. Leaf biomass of Calliandra calothyrsus, Senna spectabilis, Croton megalocarpus, Lantana camara, Sesbania sesban, and Tithonia diversifolia were incorporated into the soil at 5 Mg ha–1 for six consecutive seasons in 3 years and responses compared with those following the application of 120 kg N ha–1, 0 kg P ha–1 (0P); 120 kg N ha–1, 10 kg P ha–1; and 120 kg N ha–1 25 kg P ha–1 as urea and triple superphosphate (TSP); K was supplied in all treatments. Addition of Tithonia, Lantana and Croton increased soil resin-extractable P over that of fertilizer-amended soil throughout the first crop, but the amounts in the former treatments became similar to those for soils amended with inorganic fertilizers for subsequent crops. Addition of Sesbania, Calliandra and Senna had a similar effect on resin P as inorganic fertilizers. Total maize yields after six seasons were tripled by the application of Tithonia compared to 0P, and were higher than those of the Calliandra, Senna, Sesbania and Lantana treatments, and similar only to that of the Croton treatment. P recovered in the above-ground biomass and resin P, immediately after the implementation of the treatments, was higher in the Senna, Sesbania, Croton, Lantana and Tithonia (35–77%) treatments than in the inorganic fertilizer treatments (21–27%). The P content of organic residues, and the soluble C:total P ratio, were the main residue parameters predicting soil P availability and maize yield. All organic residues used in this study can replace inorganic fertilizers for the enhancement of P availability and maize production, while an additional benefit could be obtained from the use of Croton, Lantana and Tithonia.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 32 (2000), S. 435-440 
    ISSN: 1432-0789
    Keywords: Keywords Fertilizer ; Long-term field experiment ; Manure ; Mycorrhiza ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  A pot experiment was conducted with soil from a long-term (74-year) fertilization field experiment to compare the effects of organic and mineral fertilizers on mycorrhiza formation in clover, and mycorrhiza-mediated plant P uptake. Five treatments were selected from the field experiment representing different forms and levels of P. Mycorrhizal effects on plant growth and P uptake were estimated by comparing plants grown in untreated soil containing indigenous arbuscular mycorrhizal (AM) fungi, with plants grown in pasteurized soil. Short-term versus residual effects of fertilizer/manure were also measured by comparing treatments with or without fertilizers added at the start of the pot experiment. Mycorrhiza formation was greatest in soil that had received no P for 74 years, followed by soil having received 30 or 60 Mg ha–1 farmyard manure (FYM), and soil having received 25 or 44 kg P ha–1 in NPK fertilizers. Plant growth and P uptake were severely reduced in the absence of AM fungi for all mineral fertilizer treatments. In contrast, plants growing in soil that had received FYM grew equally well or better when non-mycorrhizal. Recent additions of NK fertilizer and FYM had no effect on mycorrhiza formation, while additions of NPK led to reduced colonization. It thus seems that moderate quantities of FYM have less adverse effects on AM than equivalent amounts of nutrients in NPK fertilizers, a phenomenon that is most likely due to a temporal difference in P availability and its gradual release that balance plant demand.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0975
    Keywords: Keywords Coral ; Nitrogen ; Phosphorus ; Eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract  The effect of prolonged (9 week) nutrient enrichment on the growth and photosynthetic rates of the zooxanthellate coral Stylophora pistillata was investigated. The main questions were: (1) what is the exposure time needed to induce measurable change in growth rate? (2) which are the concentrations of nitrogen and phosphorus required to cause changes in these rates? (3) what is the recovery potential of the corals after the nutrient stress? For this purpose, three tanks (N, P, NP) were enriched with ammonium (N), phosphorus (P) or both nutrients (NP), respectively. A fourth tank (C) served as a control. The growth of 40 nubbins (10 in each tank) was monitored during four periods: period 1 (nutrient-poor conditions), period 2 (10 μm NH4 and/or 2 μm PO4 enrichment), period 3 (20 μm NH4 and/or 2 μm PO4) and period 4 (nutrient-poor conditions). Period 4 was performed to study the recovery potential of corals after a nutrient stress. During period 1, growth rates remained constant in all tanks. In the P tank, growth rates declined during the two enrichment periods, with a total decrease of 60% by the end of period 3. In the N tank, growth rates remained nearly constant during period 2 but decreased in period 3 (60% decrease). In the NP tank, 50% and 25% decreases were observed during periods 2 and 3. At the end of the recovery period, a regain in growth rate was observed in the N and NP tanks (35 and 30% increase, respectively, compared with the rates measured at the end of period 3) and growth rates returned to 60% of the initial rates. By contrast, in the P tank, there was no regain in growth and a further decrease of 5% was observed. Rates of photosynthesis were often higher during the enriched than the nutrient-poor period (up to 150% increase). Corals with the highest percent increases in maximal gross photosynthetic rate (P g max ) had the smallest decreases in growth rate due to nutrient enrichment. In conclusion, high ammonium (20 μm) and relatively low phosphorus concentrations (2 μm) are required to induce a significant decrease in coral growth rate. The largest reduction was observed with both ammonium and phosphorus enrichment. The decrease in growth rate was rapid following nutrient enrichment, since a 10% decrease or more could be observed after the first week of treatment.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    International archives of occupational and environmental health 73 (2000), S. S69 
    ISSN: 1432-1246
    Keywords: Key words Epidemiology ; Fibers ; Occupation ; Review ; Textile
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objectives: Natural organic fibers are used in large quantities in the production of paper products and textiles. They are also constituents of food and added to food to promote health. The objective of this review is to evaluate the health effects of natural organic fibers. The health effects of dietary fibers are excluded from the review. Methods: This is a literature review. Results: Exposure to these fibers in industry is usually not characterized as fibers but as dust. Rather dusty conditions have been reported in both paper and textile industries with concentrations up to and above 30 mg/m3. Both in the paper and textile industry inorganic fibers may occur making it hard to evaluate health effects of natural organic fibers from studies of workers in the paper and textile industry. There seems to be no increased risk of mesothelioma, lung cancer or lung fibrosis in workers exposed to natural organic fibers in contrast to workers exposed to inorganic crystalline fibers as asbestos. However, workers with a heavy exposure to paper dust or textile dust seem to have an increased risk of obstructive lung disease and bronchitis. These effects have not been causally linked to the fibrous shape of the particles but rather to the dust, chemicals absorbed on the dust or microorganisms occurring together with the dust. There is some indication that work in the textile industry may increase the risk of sinonasal cancer, but the etiological agents are unknown. Conclusion: Natural organic fibers are not causally linked with the well-known effects of some inorganic fibers, i.e. mesothelioma, lung cancer, lung fibrosis or some pleural diseases. The health effects of natural organic fibers, e.g. irritative effects, seem not to be linked to their fibrous shape.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Der Pathologe 21 (2000), S. 39-54 
    ISSN: 1432-1963
    Keywords: Schlüsselwörter Chronische myeloische Leukämie ; Megakaryozyten ; Fasern ; Erythropoese ; Makrophagen ; Klinische Befunde ; Immunhistochemie ; Knochenmarkbiopsie ; Key words Chronic myelogenous leukemia ; Megakaryocytes ; Fibers ; Erythroid precursors ; Macrophages ; Clinical findings ; Immunohistochemistry ; Morphometry ; Bone marrow biopsies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary An immunohistochemical and morphometric study was performed on bone marrow biopsies in 604 patients with chronic myelogenous leukemia (CML) to compare morphological and clinical features and to evaluate effects of interferon (IFN) and chemotherapy. Following morphometry significant correlations were calculated between number of CD61+ megakaryocytes, including their precursors with fiber density. This finding is in line with the close functional relationship between megakaryopoiesis and fibroblasts regarding the complex pathomechanism of myelofibrosis. The latter was observed in about 28% of patients already at diagnosis. In a similar way, the frequency of CD68+ macrophages was correlated with the amount of Ret40f+ nucleated erythroid precursors, implicating an involvement of this cell lineage in iron turnover, hemoglobin synthesis, and degradation of the expelled nuclei from normoblasts. The (α-D-galactosyl residue-expressing) Pseudo-Gaucher cells were detectable in 30% of pretreatment specimens. Moreover, significant associations were calculable between reduction in erythropoiesis or increase in fibers with clinical features such as hemoglobin level, percentages of myelo- and erythroblasts in the peripheral blood, and spleen size. These variables are in keeping with more advanced stages of CML. Based on our morphometric evaluations, a classification into three different histological subgroups: granulocytic, megakaryocytic, and myelofibrotic was carried out. This simplified staging system was correlated with corresponding sets of hematological data. Sequential biopsies in 173 patients with monotherapy by IFN, hydroxyurea (HU), or busulfan (BU) revealed a fibrogenic effect of IFN in contrast to a fiber-reducing property of HU. The dynamics of myelofibrosis and changes of major cell lineages during treatment were readily demonstrable by calculating corresponding indices. These included the ratios between quantitative differences of corresponding variables at repeated examinations and time. Thus, in patients with complete hematological remission following IFN administration, regeneration of erythropoiesis was found to be accompanied by an increase in the total number of CD68+ macrophages, including activated subpopulations. Histological subgroups showed a transition from a (nonfibrotic) granulocytic and megakaryocyte pattern to the myelofibrotic subtype in about 40% of patients. This change was opposed to a numerical reduction in the myelofibrotic subtype which occurred in 17 patients (36%), but predominantly in those under HU therapy. In conclusion, the striking heterogeneity of bone marrow features in CML warrants a careful morphological evaluation of trephine biopsies and appropriate means of processing to achieve relevant correlations with clinical data and, thus, allows a more elaborate insight into the dynamics of the disease process.
    Notes: Zusammenfassung Bei 604 Patienten mit einer chronischen myeloischen Leukämie (CML) wurde anhand von Beckenkammbiopsien eine immunhistochemische und morphometrische Studie durchgeführt, um morphologische und klinische Befunde miteinander zu vergleichen und die Auswirkungen der Interferon- (IFN) und Chemotherapie abzuklären. Anhand der morphometrischen Analyse konnten signifikante Korrelationen zwischen der Anzahl CD61+-Megakaryozyten einschließlich ihrer Vorläuferzellen mit der Faserdichte berechnet werden. Dieser Befund spiegelt die enge funktionelle Beziehung zwischen der Megakaryopoese und den Fibroblasten im Hinblick auf den komplexen Pathomechanismus der Myelofibroseentstehung wider. Diese war bei etwa 28% der Patienten bereits zum Diagnosezeitpunkt zu beobachten. In ähnlicher Weise war die Anzahl der CD68+-Makrophagen mit der Menge an Ret40f+-kernhaltigen erythropoetischen Vorläuferzellen korreliert, was durch die Einbindung dieser Zellinie in den Eisenstoffwechsel, die Hämoglobinsynthese sowie den Abbau der ausgestoßenen Normoblastenkerne in Zusammenhang gebracht werden kann. Die (α-D-Galaktosylreste-expremierende) Pseudo-Gaucherzellen ließen sich in 30% der Biopsien vor Behandlung nachweisen. Weiterhin konnten signifikante Beziehungen zwischen einer Reduktion der Erythropoese oder einer Zunahme der Verfaserung mit klinischen Parametern wie dem Hämoglobinspiegel, dem Anteil an Myelo- und Erythro-Normoblasten im peripheren Blut und der Milzgröße berechnet werden. Diese Variablen kennzeichnen offensichtlich mehr fortgeschrittene Stadien der CML. Entsprechend unserer morphometrischen Auswertung wurde eine Klassifikation in drei unterschiedliche histologische Subgruppen vorgenommen: granulozytisch, megakaryozytisch und myelofibrotisch. Dieser vereinfachten histologischen Einteilung waren entsprechende hämatologische Daten zuzuordnen. Sequenzbiopsien an 173 Patienten, die eine Monotherapie mit IFN, Hydroxyurea (HU) oder Busulfan (BU) erhielten, zeigten einen fibrogenetischen Effekt von IFN im Gegensatz zu einer eher faserreduzierenden Eigenschaft von HU. Die Dynamik der Myelofibroseentwicklung und die entsprechende Veränderungen der hauptsächlichen Zellinien während der Behandlung ließen sich am besten durch eine Kalkulation von Indizes verdeutlichen. Diese beinhalteten das Verhältnis aus quantitativen Unterschieden der einzelnen Variablen in den wiederholt durchgeführten Entnahmen und den zugeordneten zeitlichen Differenzen. So war bei Patienten mit einer kompletten hämatologischen Remission nach IFN-Gabe die Regeneration der Erythropoese zusammen mit einem Anstieg in der Anzahl CD68+-Makrophagen einschließlich ihrer aktivierten Subpopulation auszumachen. Die histologischen Subgruppen ließen bei fortlaufenden Untersuchungen einen Übergang sowohl von einem (nicht verfaserten) granulozytären wie auch megakaryozytären Subtyp in eine myelofibrotische Gruppe bei etwa 40% der Patienten erkennen. Dieses Phänomen stand im Gegensatz zu einer anzahlmäßigen Reduzierung des myelofibrotischen Typs vor allem bei Patienten unter HU-Therapie in 17 Fällen (36%). Zusammengefaßt erfordert die auffallende Heterogenität der Knochenmarkbefunde bei der CML eine sorgfältige morphologische Auswertung von Biopsien mit geeigneten Methoden, um relevante Korrelationen zwischen klinischen Daten zu berechnen und somit einen besseren Einblick in die Dynamik der Krankheitsentwicklung zu gewinnen.
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  • 6
    ISSN: 1615-6102
    Keywords: Allium porrum ; Arbuscular mycorrhiza ; Mitotic cycle ; Phosphorus ; Root apex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Arbuscular mycorrhizal (AM) fungi significantly improve plant growth in soils with low phosphorus availability and cause many changes in root morphology, similar to those produced by increased P nutrition, mainly depending on root apex size and activity. The aim of this work was to discriminate between the morphogenetic role of AM fungi and P in leek (Allium porrum L.) by feeding mycorrhizal and nonmycorrhizal plants with two nutrient solutions containing 3.2 or 96 μM P and examining specific parameters related to adventitious root apices (apex size, mitotic cycle, and RNA synthesis). The results showed that AM fungi blocked meristem activity as indicated by the higher percentages of inactive apices and metaphases in the apical meristem of mycorrhizal plants, whereas the high P supply lengthened the mitotic cycle without blocking the apices, resulting in steady, slow root growth. The possible involvement of abscisic acid in the regulation of root apex activity is discussed.
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  • 7
    ISSN: 1435-5604
    Keywords: Key words Calcium ; Phosphorus ; PTH ; Bone meal powder
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To evaluate the effects of bone meal powder (BEC) on calcium and phosphorus metabolism, a calcium absorption test was conducted using a preparation of calcium carbonate (CAC) as the control drug. A total of 12 healthy volunteers, consisting of 6 younger (aged 20–29 years, 3 men and 3 women) and 6 older (aged 60–69 years, 3 men and 3 women) persons, were subjected to a double-blinded crossover study. Serum calcium (s-Ca) level significantly increased to 105.3% ± 1.9% (P 〈 0.01 vs the basal value; mean ± SD) from the basal value in the BEC group and to 104.4% ± 2.7% (P 〈 0.01) in the CAC group at 3 h post load. Urinary excretions of calcium (u-Ca/glomerular filtration rate, u-Ca/GF) after BEC and CAC load rose to 226.6% ± 154.5% (P 〈 0.05) and 211.1% ± 148.0% (P 〈 0.05), respectively. Serum phosphorus (s-P) levels after BEC load increased to 110.0% ± 15.1% (P 〈 0.05), whereas that after CAC load showed no significant change (99.3% ± 7.9%). On the other hand, urinary excretion of phosphorus (u-P/GF) after CAC load decreased to 60.0% ± 32.4% (P 〈 0.01) and that in the BEC group showed no significant change (92.5% ± 49.5%). The increase in s-Ca led to decrease in serum intact parathyroid hormone (i-PTH) level [77.3% ± 33.4% (P 〈 0.05) for BEC and 69.5% ± 20.3% (P 〈 0.01) for CAC] although s-P was increased by the BEC load. The responses to BEC and CAC administration were compared in the younger and the older groups. The responses in the younger and the older group showed fundamentally the same trends and to the same extent. However, the changes in serum ionized calcium (i-Ca) and i-PTH levels at 1.5 h post load were significantly smaller in the older group than in the younger group (P 〈 0.01; P 〈 0.05). The increment in s-P level after BEC load in the older group was larger than that in the younger group. In conclusion, BEC can modulate not only calcium but also phosphorus metabolism in both younger and older subjects. Further investigations are required to evaluate the effects of BEC on bone density and safety for renal function in long-term observations.
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  • 8
    ISSN: 1434-1948
    Keywords: Hypercoordinated phosphorus ; Hypervalent phosphorus ; Phosphorus ; Diphosphonium compounds ; Ionomers ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Starting from R′R2P (R′ = 8-dimethylamino-1-naphthyl) containing a donor dimethylamino group, the new phosphonium salts [R′R2P(CH2Ph)]+Br- [R = Me (9) or Ph (10)] and [R′R2P(p-CH2C6H4CH2)PR2R′]2+[2Br]2- [R = Ph (12)] have been prepared. An interaction between the N and P atoms is evident from the X-ray crystal structure of 10 the N-P distance being less than the sum of the van der Waals radii of the 2 atoms. The geometry of 10 is that of a monocapped tetrahedron whereas the X-ray crystal structure determination shows essentially regular tetrahedral geometry for the analogous compound without the donor amino group, [(1-Np)Ph2P(CH2Ph)]+Br- (11). Treatment of 1,5-bis(dimethylamino)-2,6-dilithionaphthalene with chlorodiphenylphosphane gave 1,5-bis(dimethylamino)-2,6-bis(diphenylphosphanyl)naphthalene (8) which in the presence of methyl iodide afforded the diphosphonium salt [1,5-bis(dimethylamino)-2,6-bis(diphenylmethylphosphonium)naphthalene]2+[2I]2- (13). Similarly, treatment of 8 with 1 equivalent of benzyl bromide gave the monophosphonium salt [1,5-bis(dimethylamino)-2diphenylbenzylphosphonium-6-diphenylphosphanyl-naphthalene]+[Br]- (14) whereas in the presence of 2 equivalents of the same reagent [1,5-bis(dimethylamino)-2,6-bis(diphenylbenzylphosphonium)naphthalene]2+[2 Br]2- (15) was obtained. The ionomer poly([(1,5-bis{dimethylamino}2,6-bis{diphenylphosphonium}naphthalene)-(P,P-p-xylylene)]2+[2 Br]2-) (16), soluble in liquid SO2, was prepared by treatment of 8 with α,α′-dibromo-p-xylene.
    Additional Material: 2 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 103-112 
    ISSN: 1434-1948
    Keywords: Ab initio calculations ; Ionization potentials ; Phosphorus ; Heterocycles ; Small ring systems ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio quantum chemical calculations have been used to explore the P3H3 potential energy surface focussing on the ring-chain rearrangements of the three-membered ring in (PH)3 (1), the parent triphosphirane. Relative energies between stationary points were estimated using the QCISD(T)/6-311G(d,p) method based on MP2/6-31G(d,p) geometries and corrected for zero-point contributions. Ring strain, proton affinities, ionization and excitation energies and heats of formation have been evaluated using larger basis sets, e.g. 6-311++G(3df,2p). The cyclic trans-triphosphirane (1a) is the most stable P3H3 isomer and lies about 40 kJ/mol below the open-chain phosphanyldi-phosphene (H2P-P=PH). The decrease of ring strain in three-membered rings when CH2 is replaced by PH is confirmed. Triphosphirane 1a is a virtually strain-free ring and even gains some stabilization relative to three separate P-P single bonds. The reduced ring strain also helps diminish the phosphorus inversion barrier to 224 kJ/mol compared to the monocyclic isomers of (CH2)(PH)2 and (CH2)2(PH). Compound 1a follows a pure ring-opening or a 1,2-hydrogen shift rather than a combined motion pathway, in fundamental contrast with corresponding processes of diphosphirane and phosphirane. This is due to the existence of an open-chain P3H3 phosphorane intermediate stabilized by allylic conjugation. The pericyclic ring-opening of 1a is the most favored process but the energy barrier in the gas phase is about 180 kJ/mol high. Electron density is largely delocalized within the three-membered P3 ring not only in the C3v-symmetric 1b (all-cis) but also in 1a (Cs). The proton affinity of 1a is similar to that of PH3. The proton affinities decrease with n in cyclo-(CH3)3 -n(PH)n and their values were obtained: PA(1a) = 777 ±10, PA(diphosphirane) = 799 ±10 and PA(phosphirane) = 802 ±10 kJ/mol. Heats of formation are evaluated as follows (ΔH°f0 at 0 K in kJ/mol): 1a, 70 ±10; cyclo-(PH)2(PH2)+ (protonated 1a), 821 ±10; diphosphirane, 85 ±10; cyclo-(CH2)(PH)(PH2)+ (protonated diphosphirane), 814 ±10; phosphirane, 86 ±10; and protonated phosphirane, 812 ±10 kJ/mol. All P rings remain cyclic following ionization to the radical cations. Adiabatic ionization energies (IEa) are estimated as: 1a and diphosphirane, 9.3 ±0.3 eV and phosphirane 9.5 ±0.3 eV. The first UV absorption band shifts toward the longer wavelength region on going from phosphirane to 1a. The GIAO/B3LYP computed magnetic shieldings for 1a and related molecules reveal a clear relationship between the narrow bond angles in the rings and their unusually strong magnetic shielding. The similarity of the predicted 31P-NMR signals in 1a and its heteroanalog diphosphirane, (CH2)(PH)2, can be rationalized in terms of a compensation of the carbon-substituent effect (downfield shift) and the bond-bending effect imposed by the ring (upfield shift).
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 417-421 
    ISSN: 1434-1948
    Keywords: Phosphorus ; Benzynezirconocenes ; Azazirconacyclopentenes ; Exchange reactions ; 1,2-Azaphosphindole ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The first 1,2-azaphosphindoles 14a,b, 15a,b were obtained in a straightforward manner upon heating diphenylzirconocene in the presence of a cyanophosphane, which afforded azazirconacyclopentenes 11a,b which can be reacted with various dichlorophosphanes. The use of the tetrachlorodiphosphane Cl2P(CH2)2PCl2 instead of a dichlorophosphane allowed the preparation of the bis(1,2-azaphosphindoles) 19, 19′. The monosulfur adduct of the azaphosphindole 14a, i.e. 16a, was characterized by X-ray structure analysis. Alkylation of 14a or 16a with methyltrifluoromethane sulfonate occurred selectively on the intracyclic phosphorus atom or on the sulfur atom, giving the salts 20 or 21, respectively.
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  • 11
    ISSN: 1434-1948
    Keywords: Thiophosphites ; X-ray diffraction ; Manganese ; Iron ; Phosphorus ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thioesters of the phosphorous acid containing cymantrenyl and ferrocenyl substituents at sulfur were obtained for the first time from the reaction of organometallic disulfides with white phosphorus. According to an X-ray diffraction study tricymantrenyl trithiophosphite adopts an unusual asymmetric cis, gauche, trans conformation along the P-S bonds with respect to the phosphorus lone electron pair. Triferrocenyl trithiophosphate possesses a classical propeller-like structure in the solid state which is different from its oxygen analogue.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 4 (1969), S. 210-223 
    ISSN: 1432-0827
    Keywords: Invertebrate ; Tetracycline ; Growth ; Fibers ; Test
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La croissance de la carapace deStrongylocentrotus intermedius est étudiée à l'aide de la tétracycline. Des specimens de l'été ne présentent pas de fluorescence dans les plaques, sauf dans le système apical et les régions voisines. Un faisceau d'éléments fibreux, présentant une autofluorescence blanche laiteuse, est orienté perpendiculairement à chaque ligne de suture. Les spécimens de l'hiver ne présentent ces éléments qu'après décalcification des coupes. La croissance de chaque plaque, chez ces derniers s'effectue de la façon suivante: suture longitudinale » surface interne = mamelon et bosse du tubercule 〉 suture transversale 〉 surface externe de la base de l'épine dorsale 〉 surface externe de la plaque. La carapace adulte augmente de taille selon deux mécanismes de croissance: d'une part, par adjonction de nouvelles plaques au système apical et, d'autre part, par apposition sur des régions données de chaque plaque. Il apparait que des éléments fibreux sont intéressés par la croissance de la carapace et qu'un mécanisme différent de croissance s'observe dans les carapaces de l'été et de l'hiver. Le système apical semble se calcifier selon un mécanisme spécifique qui permet une formation active de plaques nouvelles pendant toute l'année.
    Abstract: Zusammenfassung Das Wachstum des Skeletes vonStrongylocentrotus intermedius wurde mit Hilfe von Tetracyclin untersucht. Bei Sommerexemplaren konnte die Tetracyclinfluorescenz in den Platten nicht beobachtet werden, außer im apicalen System und seiner anliegenden Umgebung. Eine Menge von fibrösen Elementen mit einer milchig-weißen Autofluorescenz war senkrecht zu jeder Nahtlinie angeordnet. Bei Winterexemplaren waren diese Elemente nur in demineralisierten Schnitten deutlich sichtbar. Der Wachstumsgradient jeder Platte war bei Winterexemplaren der folgende: Longitudinalnaht » innere Oberfläche = Terminalknopf und Hals der Tuberkel 〉 Latitudinalnaht 〉 Oberfläche der Basis des Stachels 〉 äußere Oberfläche der Platte selbst. Das ausgewachsene Skelet als Ganzes vergrößert seinen Umfang auf zwei Wachstumsarten, einerseits durch Zusatz von neuen Platten zum apikalen System, anderseits durch Zuwachs an bestimmten Stellen von jeder Platte. Die Resultate lassen vermuten, daß fibröse Elemente am Skeletwachstum beteiligt sind und daß der Mechanismus dieses Wachstums bei Sommer- und bei Winterexemplaren verschieden ist. Es wäre denkbar, daß das apikale System auf einen spezifischen Mechanismus der Verkalkung ansprechen würde, welcher eine aktive Bildung neuer Platten während des ganzen Jahres erlaubt.
    Notes: Abstract Growth of the test ofStrongylocentrotus intermedius was examined with the aid of tetracycline. In summer specimens, tetracycline fluorescence was not observable in the plates, except in the apical system and its adjacent area. An array of fibrous elements with a milky white autofluorescence was oriented perpendicularly to each suture line. In winter specimens the elements were evident only in demineralized sections. The growth gradient of each plate estimated on winter specimens was as follows: longitudinal sture » inner surface = mammelon and part of boss in tubercle 〉 latitudinal suture 〉 outer surface of base of spine shaft 〉 outer surface of plate itself. The mature test as a whole increases in size by two modes of growth, an addition of new plates to the apical system and an accretion on fixed sites of each plate. The results suggest that fibrous elements are involved in the test growth, and that there is a different mechanism of the test growth between summer and winter specimens. The apical system may be equipped with a specific mechanism of calcification which permits an active formation of new plates throughout the year.
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  • 13
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    Electronic Resource
    Springer
    Calcified tissue international 4 (1969), S. 78-83 
    ISSN: 1432-0827
    Keywords: Bone ; Calcification ; Osteomalacia ; Phosphorus ; Vitamin D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les effects d'une dose de 1 mg de vitamine D3 (40 000 Unités,) administrée par voie intra-veineuse, ont été étudiés sur l'histologie osseuse et le métabolisme du phosphore chez 19 sujets contrôles dont l'histologie était normale et 28 malades présentant les caractères histologiques de l'ostéomalacie par carence vitaminique D. L'administration de la vitamine D n'a entraîné aucune modification histologique ou biologique significative chez les sujets contrôles. Mais chez les ostéomalaciques, il est apparu en moins de sept jours une augmentation très significative du front de calcification à l'interface tissue-ostéoïde-tissue-calcifié. Cette modification s'accompagnait d'une ascension progressive de la phosphatémie et de la réabsorption tubulaire du phosphore atteignant dans le même délai des valeurs normales.
    Abstract: Zusammenfassung Bei 19 Patienten mit normaler Knochenhistologie und bei 28 Patienten mit histologisch gesicherter Osteomalacie wurde die Wirkung von 1 mg Vitamin D3 (40000 Iv) i.v. auf die Knochenhistologie und den Phosphatmetabolismus untersucht. Bei den Kontrollpatienten konnten keine signifikanten Änderungen nach Vitamin D festgestellt werden, wogegen die Osteomalacie-patienten innerhalb von 7 Tagen eine deutliche Zunahme der Verkalkungszone an der Grenze zwischen Osteoid- und Knochengewebe zeigten. Diese Änderung war von einer fortschreitenden Zunahme des Serum-Phosphates, verbunden mit einer gesteigerten renalen tubulären Rückabsorption des Phosphates begleitet; beide kehrten anschließend gleichzeitig wieder zur Norm zurück.
    Notes: Abstract The effect of a 1 mg dose of intravenous Vitamin D3 (40,000 i.u.) on bone histology and phosphate metabolism was investigated in 19 patients with normal bone histology and 28 patients with histological evidence of osteomalacia. No significant changes occurred in the control patients after Vitamin D but the patients with osteomalacia showed a marked increase, within seven days, in the proportion of osteoid having a calcification front. This was accompanied by a progressive rise in the serum phosphate, which was associated with an increase in the renal tubular reabsorption of phosphate to normal.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 101 (1969), S. 323-337 
    ISSN: 1432-0878
    Keywords: Vitreous body ; Hyalocytes ; Three-dimensional network ; Fibers ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The vitreous body of the rat eye was studied by scanning electron microscopy. The freeze-dried specimens were either unfixed, freshly frozen or fixed and rinsed before being frozen. The vitreous body is surrounded by a coat of intercellular material covering a thin sheath of chiefly parallel fibers. The latter forms the base for a regularly organized three-dimensional network of fibers. The interfibrillar spaces are filled with ground substance and also contain a few cells. The shape of the cells varies from bipolar to polyhedronal. Their interconnected processes are usually undivided. The functional importance of this complex regular organization of the fibers and cells in the vitreous body is stressed.
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  • 15
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    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 8 (1969), S. 660-671 
    ISSN: 0570-0833
    Keywords: Phosphorus ; History of chemistry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Exactly 300 years ago in the city of Hamburg, a certain Hennig Brand, self-styled doctor medicinae, and chymist, discovered a strange substance in human urine, which was later called phosphorus (light bearer), a name then common to various luminous substances, and which created much excitement in the latter years of the 17th century on account of its properties. However, it was not Brand who profited from the discovery but others: Johann Daniel Krafft, Johann Kunckel, and Gottfried Wilhelm Leibniz, men who knew only too well how to exploit the weaknesses of the discoverer. “Cold fire”, Brand's own name for the new substance, was originally regarded as elemental light or fire, and it was not until the conception of the antiphlogistic theory by Antoine Laurent Lavoisier that the proper position of phosphorus among the chemical elements was recognized. In fact, the element played a decisive role in the overthrow of the phlogiston doctrine, a little over one hundred years after its discovery and almost two hundred years ago.
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  • 16
    ISSN: 0570-0833
    Keywords: Aluminum ; Silicon ; Boron nitride ; Phosphorus ; Polymers ; Silicic acid ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The differences between compounds of carbon and of silicon are discussed, and the role of silicon as a fundamental structural component in inanimate nature is described. Starting with silicic acid and silicates, the structure and properties of the silicones and of compounds having Si—C—Si skeletons are described. The possibilities for the formation of high molecular-weight compounds between elements of Groups 3 and 5 of the periodic system are considered, with particular reference to boron nitride and to aluminum-phosphorus compounds.
    Additional Material: 10 Ill.
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  • 17
    ISSN: 0570-0833
    Keywords: Electrophilic reactions ; Substitution ; Phosphorus ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions belonging to the formal category of electrophilic substitutions at phosphorus are classified according to mechanism and the coordination number of the phosphorus atom.
    Additional Material: 1 Tab.
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  • 18
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    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 7 (1968), S. 278-285 
    ISSN: 0570-0833
    Keywords: Polyamides ; Fibers ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High molecular weight poly-β-amides with fiber-forming properties (repeating unit—NH—CR2—CR2—CO—) differ from the polyamides of the nylon series in that the amide groups are much more closely spaced. These polymers are thus the nearest of the synthetic polyamides to natural silk. The production of poly-β-amides was made possible by a recent synthesis of β-lactams from olefins and chlorosulfonyl isocyanate. The anionic polymerization of the β-lactams gives poly-β-amides containing up to 10 000 monomer units in the chain. The molecular weight can be controlled as desired by means of initiators and chain terminators, and the properties can be varied within wide limits by the choice of the β-lactam or by copolymerization of several β-lactams. Remarkable differences are observed between polymers containing structural units in the threo form and those containing erythro structural units. The poly-β-amides can be spun into fibers having valuable textile properties.
    Additional Material: 4 Ill.
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  • 19
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    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 5 (1966), S. 53-57 
    ISSN: 0570-0833
    Keywords: Aluminum ; Phosphorus ; Silicon ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The formation and properties of silicon-phosphorus and aluminum-phosphorus compounds are described. Silylphosphines are decomposed solvolytically by H2O, C2H5OH, NH3, hydrogen halides, C2H5I, and boron halides at the Si—P bond; decomposition may be preceded by formation of an addition compound. Extensive side reactions during the reaction of halogenosilanes with LiPEt2The following abbreviations are used in this paper: Et = C2H5; Me = CH3; M = alkali metal (formation of Et2P—PEt2, HPEt2, Si-rich residues) are due to an excess of LiPEt2 in the reaction mixture. The reaction of LiPEt2 with AlCl3, AlHCl2, and AlH2Cl leads to definite aluminum-phosphorus compounds if only one PEt2 group is present per Al atom, e.g. in (Cl2Al-PEt2)3, or if salts such as Li[Al(PEt2)4] and Li[AlH2(PEt2)2] can be formed with an excess of LiPEt2.
    Additional Material: 1 Tab.
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  • 20
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    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 457-471 
    ISSN: 0570-0833
    Keywords: Color ; Azo compounds ; Azobisphosphoric acid ; Phosphorus ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Attempts to explain the surprising violet color of the new azobisphosphonic acid derivatives Y2OP—N=N—POY2 have led to the preparation and spectroscopic characterization of more than 60 azo compounds. The long-wavelength n → π* transitions on which the color depends exhibit regularities which justify the assumption of substitutent-specific absorption increments. The complex relation between color and constitution of azo compounds can be qualitatively explained with the aid of orbital models. Infrared and ultraviolet spectral data show that conjugation is inhibited by tetra-coordinated phosphorus (V). the π-system of these compounds therfore comprises only for atoms, P·N·N·P. The unexpected violet color of the phosphorus azo compounds can be ascribed to a π*/d orbital interaction. The substituent effects described have general significance, and n→π*transitions of other chromophores are similarly affected.
    Additional Material: 14 Ill.
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  • 21
    ISSN: 0570-0833
    Keywords: Free radicals ; Polyamides ; Fibers ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The formation of free radicals during the process of drawing of spun fibers was observed for the first time with two polyoxamides. The fibers turn red, and an ESR signal can be detected. Both, color and ESR absorption are not permanent. The decrease in the intensity of the ESR absorption and the change in the optical reflectance with time, as well as the dependence of the decoloration on temperature were investigated. The action of high-energy radiation on the polyoxamides also leads to a red coloration and gives rise to ESR signals. It is concluded that the red color is due to free radicals associated with the oxamido group.
    Additional Material: 5 Ill.
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  • 22
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    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 1023-1038 
    ISSN: 0570-0833
    Keywords: Heterocycles ; Phosphorus ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of heterocycles containing phosphorus is described. The chemical behavior of ring systems containing trivalent phosphorus is mainly determined by their phosphine character; heterocyclic behavior in the ordinary sense is shown by rings containing functional groups. Syntheses and reactions of cyclic compounds of pentavalent and hexavalent phosphorus are particularly interesting.
    Additional Material: 3 Tab.
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  • 23
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    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 1007-1013 
    ISSN: 0570-0833
    Keywords: Sulfur ; Selenium ; Tellurium ; Phosphorus ; Organometallic compounds ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bond fission of molecular sulfur, selenium, and tellurium by lithiotriphenylmetal compounds (of Ge, Sn, Pb) is summarized. The products are suitable as starting materials for synthesis of new “ether analogues”. Transphenylation with tetraphenylstannane is interpreted as a high-temperature variant of the usual fission of chalcogen molecules by nucleophilic reagents. In principle, transphenylation can be applied also to other elements, as is illustrated for phosphorus. In the syntheses achieved, many of the tin-phosphorus compounds arising as intermediates can be isolated.
    Additional Material: 6 Tab.
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  • 24
    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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  • 25
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    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 3 (1964), S. 460-470 
    ISSN: 0570-0833
    Keywords: Heat resistance ; Fibers ; Polymers ; Materials science ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This survey is principally concerned with papers published since 1959 on hydrocarbon polymers, aliphatic poly(terephthalamide) fibers, poly(hydroxybenzoic acid) films, poly(oxadiazole) fibers, poly(benzimidazole) films, poly(phenyltriazole) films, poly(pyromellitimide) films, and fibers from cyclized poly(acrylonitrile). All these materials have extremely high melting points and satisfactory in-use characteristics at high temperatures.
    Additional Material: 5 Ill.
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  • 26
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    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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  • 27
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    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.
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  • 28
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 410-420 
    ISSN: 0570-0833
    Keywords: Oligomers ; Pleionomers ; Polymers ; Fibers ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The term “oligomer” is defined, and a survey of methods for the isolation and synthesis of cyclic and linear oligoesters, oligourethanes, oligo(acrylonitriles), and oligoamides is presented. The oligomers serve a valuable function as model substances for the investigation of many properties of the corresponding high polymers. This is shown using several examples (infrared spectroscopy, X-ray spectroscopy, viscosity).
    Additional Material: 1 Ill.
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  • 29
    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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  • 30
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    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.
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  • 31
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    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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  • 32
    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.
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  • 33
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    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 532-537 
    ISSN: 0570-0833
    Keywords: Polyacrylonitrile ; Fibers ; Azatrimethinecyanines ; Dyes/Pigments ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Like all basic dyes, azatrimethinecyanines possess a good dyeing affinity for acrylic fibers. Compounds with isolated nitrogen atoms in the trimethine chain show insufficient light fastness, whereas good to excellent fastness to light is displayed by compounds having neighboring nitrogen atoms in the chain. Thus, a working hypothesis stating that the light fastness of trimethinecyanines on acrylic fibers is improved by progressive replacement of methine groups by nitrogen atoms has been partially confirmed.
    Additional Material: 3 Tab.
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  • 34
    ISSN: 0570-0833
    Keywords: Elastomers ; Fibers ; Polyurethanes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Highly elastic polyurethanes suitable for fiber production can be obtained by various synthetic routes based on diisocyanate polyaddition processes. Macrodiisocyanates obtained from long chain diols and diisocyanates are allowed to react with polyamines during fiber formation (chemical spinning process) or the macrodiisocyanates are treated in solvents (e.g. dimethylformamide) with polyamines to give highly viscous, spinnable solutions of polymer. Both methods yield highly elastic polymers with wide-mesh network structures. The production of polyurethane fibers and their structures and physical properties are described.
    Additional Material: 6 Ill.
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  • 35
    ISSN: 0570-0833
    Keywords: Copolymers ; Fibers ; Vinylidenedicarbonitrile ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vinyldendicarbonitrile (Vinylidene cyanide) on free redical catalyzed copolymerization shows a much stronger tendency to form 1:1 alternating copolymers than acrylonitrile. While bulk poly(vinylidene cyanide) fails to crystallize, despite its molecular symmetry, several alternating copolymers are readily crystallizable, notably those containing butadiene, isoprene, isobutylene, or vinylidene chloride. Fibers have been prepared from a number of the higher melting copolymers and examined for physical properties. Fibers from the vinyl acetate and vinyl chloride copolymers show expectional elastic behavior both when dry and wet. The fiber from the vinylidene cyanide |vinyl acetate alternating copolymer (Darvan® nytril fiber) is only moderately oriented and is characterized by exceptional softness and excellent elastic recovery and resilience, both when dry and wet.
    Additional Material: 9 Ill.
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  • 36
    ISSN: 0570-0833
    Keywords: Long periods ; Polyethylene ; Fibers ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Meridional reflections appearing in small-angle X-ray diffraction diagrams of drawn polyethylene are caused by a nearly periodic arrangement of crystalline and disordered regions. The long period, which is determined by the average distance between two consecutive crystallites, depends on the method of preparing the sample. The time and temperature dependences of the positions of the small-angle reflections have been investigated. The growth of the long period of unoriented bulk polyethlene and polyethylene single crystal follows the same time dependence as that of stretched films. However, characteristic differences were obseved in the relationship between density and long period; they are attributed to the fact that in single crystals and in material crystallized from the melt, the chains are folded at the boundaries of the crystallites, whereas this in not the case in stretched polyethylene.
    Additional Material: 25 Ill.
    Type of Medium: Electronic Resource
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