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  • 1
    Electronic Resource
    Electronic Resource
    Political Data in 1992 (1993)
    Oxford, UK : Blackwell Publishing Ltd
    European journal of political research 24 (1993), S. 0 
    Details
    ISSN: 1475-6765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Political Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1475-6765.1993.tb00385.x
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  • 2
    Electronic Resource
    Electronic Resource
    Apoplastic peroxidases and ascorbate are involved in manganese toxicity and tolerance of Vigna unguiculata (2003)
    Oxford, UK : Munksgaard International Publishers
    Physiologia plantarum 117 (2003), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Excessive manganese (Mn) supply induced the formation of brown spots on leaves as typical Mn toxicity symptoms in cowpea (Vigna unguiculata L. Walp.) grown in hydroponics. Differences in Mn resistance between cv. TVu 91 (Mn-sensitive) and cv. TVu 1987 (Mn-tolerant) expressed in the density of brown spots in older leaves were due to higher Mn tissue tolerance. Apoplastic water-soluble peroxidase (POD) in the apoplastic washing fluid (AWF) was enhanced by increasing Mn leaf content and generally significantly higher in leaves of cv. TVu 91 than in cv. TVu 1987. Electrophoresis of AWF revealed the presence of several water-soluble POD isoenzymes. At toxic Mn supply, the activities of these and additional POD isoenzymes increased more in the Mn-sensitive cultivar. Levels of ascorbic acid in the apoplast and cytoplasm of the Mn-sensitive cv. TVu 91 decreased with increasing leaf Mn contents, whereas Mn-tolerant cv. TVu 1987 was not affected. Mn treatment lead to a stimulation of the enzymes of the ascorbic acid regeneration system (monodehydroascorbic acid reductase and glutathione reductase) in both cultivars, but the activation of glutathione reductase was clearly more enhanced in the Mn-tolerant cultivar TVu 1987. The results provide circumstantial evidence that apoplastic ascorbate and peroxidases are involved in the expression of Mn toxicity and genotypic Mn tolerance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.2003.00022.x
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  • 3
    Electronic Resource
    Electronic Resource
    Stable Planes from Lie Groups with Planar Partitions (2000)
    Springer
    Geometriae dedicata 83 (2000), S. 217-228 
    Details
    ISSN: 1572-9168
    Keywords: Stable planes ; point-transitive group actions ; translation structures ; group partitions ; translation planes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract We describe necessary and sufficient conditions under which a topological translation structure obtained from a Lie group with planar partition can be turned into a stable plane, thereby proving a conjecture due to Stroppel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005248427064
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  • 4
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    An Evaluation of Community Development Block Grant Decisionmaking: Executive Dominance versus Issue Networks (1990)
    Urbana, Ill. : Periodicals Archive Online (PAO)
    Policy Studies Journal. 18:3 (1990:Spring) 573 
    Details
    ISSN: 0190-292X
    Topics: Political Science
    Notes: ARTICLES OF GENERAL INTEREST
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:h317-1990-018-03-000003
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  • 5
    Electronic Resource
    Electronic Resource
    Granuloma pouch assay (1980)
    Springer
    Archives of toxicology 45 (1980), S. 227-232 
    Details
    ISSN: 1432-0738
    Keywords: Granuloma pouch assay ; MNNG ; Short-term carcinogenicity tests
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Proliferation of granulation tissue on the inside of a subcutaneous (s.c.) air pocket was induced in rats by administration of 0.5 ml of 0.25% croton oil (granuloma pouch). Two days after induction of the granuloma, i.e., during the period of maximal cell growth, a single dose of 0.6 mg or 0.1 mg N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) was administered into the pouch. Fibrosarcomas of various histopathological types developed in 87% of the rats receiving the high dose and in 64% of the low dose animals. The mean latency period was 47.5 and 51.7 weeks respectively. Only one local sarcoma developed in rats treated with 0.6 mg MNNG by the s.c. route, and no tumors were observed in the groups treated with 0.1 mg s.c. The appearance of local sarcomas in the granuloma pouch tissue is correlated with previously reported frequency of point mutations (OUAR and HGPRT−) induced in granuloma fibroblasts with the same doses of MNNG. Possible mechanisms explaining the marked enhancement of the carcinogenic effect of MNNG in the granuloma pouch assay are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02419003
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  • 6
    Electronic Resource
    Electronic Resource
    Single cell analysis in toxicity testing: the mitogenic activity of thioacetamide in cultured rat hepatocytes analyzed by DNA/protein flow cytometry (1991)
    Springer
    Archives of toxicology 65 (1991), S. 454-464 
    Details
    ISSN: 1432-0738
    Keywords: Thioacetamide ; Rat ; Hepatocyte ; Flow-cytometry ; Polyploidization ; Binuclearization ; Non-genotoxic carcinogens ; Oxygen tension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rat hepatocytes were cultured at 4% O2 and 13% O2 and exposed to the nongenotoxic rodent carcinogen thioacetamide (TA) from 24 to 72 h after isolation at exposure levels between 0.01 and 0.33 mM. Hepatocytes and isolated nuclei were analyzed by DNA-protein flow cytometry. An aggregate correction procedure was applied and the proportion of S-phase, diploid, tetraploid or octoploid hepatocytes as well as binucleated cells, were measured or calculated. The proportion of S-phase cells within the diploid hepatocytes increased with increasing concentration of TA up to 3.9-fold, whereas the corresponding increase in S-phase mononucleated tetraploid cells was only 1.8-fold. S-phase binucleate tetraploid cells showed no increase. In the tetraploid hepatocytes, the mitogenic stimuli was detectable only in cultures maintained at 4% O2. The relative contribution of binuclear cells was increased 1.5-fold in the octoploid cells. It is concluded that the mitogenic activity of TA initiates DNA synthesis in diploid hepatocytes in the G1 and in the following G2 cell-cycle phase, omitting karyogenesis. The cellular protein content is not affected which indicates that the mitogenic activity of the chemical is not necessarily associated with an increase in cellular protein content. The results obtained correspond well with data of in vivo studies. The method applied therefore allows the mitogenic activity of nongenotoxic carcinogens to be detected in vitro within 48 h and their mode of action to be elucidated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01977357
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  • 7
    Electronic Resource
    Electronic Resource
    Mobilization of soil and fertilizer phosphate by cover crops (1999)
    Springer
    Plant and soil 211 (1999), S. 19-27 
    Details
    ISSN: 1573-5036
    Keywords: cover crops ; legumes ; Lupinus albus ; phosphorus efficiency ; root exudates ; rotation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Incorporation of cover crops into cropping systems may contribute to a more efficient utilization of soil and fertilizer P by less P-efficient crops through exudation of P-mobilizing compounds by the roots of P-efficient plant species. The main objective of the present work was to test this hypothesis. First a method has been developed which allows the quantification of organic anion exudation from individual cluster roots formed by P-deficient white lupin (Lupinus albus L.). Lupin plants were grown in nutrient solution at 1 μM P and in a low P loess in small rhizotrons. Organic anions exuded from intact plants grown in nutrient solution were collected from individual cluster roots and root tips sealed in small compartments by an anion-exchange resin placed in nylon bags (resin-bags). Succinate was the dominant organic anion exuded followed by citrate and malate. The mean of citrate exudation-rate was 0.06 pmol mm−1 s−1 with exudation highly dependent on the citrate concentration and on the age of the cluster roots. Exudates from cluster roots and root tips grown at the soil surface (rhizotron-grown plants) were collected using overlayered resin–agar (resin mixed with agar). Citrate exudation from cluster roots was 10 times higher than that from root tips. Fractionation of P in the cluster root rhizosphere-soil indicates that white lupin can mobilize P not only from the available and acid-soluble P, but also from the stable residual soil P fractions. In pot experiments with an acid luvisol derived from loess low in available P, growth of wheat was significantly improved when mixed-cropped with white lupin due to improved P uptake. Both in mixed culture and in rotation wheat could benefit from the P mobilization capacity of white lupin, supporting the hypothesis above. Nine tropical leguminous cover crops and maize were grown in a pot experiment using a luvisol from Northern Nigeria low in available P. All plant species derived most of their P from the resin and bicarbonate-extractable inorganic P. Organic P (Po) accumulated particularly in the rhizosphere of all plant species. There was a significant negative correlation between the species-specific rhizosphere acid phosphatase activity and Po accumulation. Growth and P uptake of maize grown in rotation after legumes were enhanced indicating that improved P nutrition was a contributing factor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004543716488
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  • 8
    Electronic Resource
    Electronic Resource
    Turbulente DrallflammenAuszug aus der Dissertation des Verfassers, Universität Karlsruhe (TH) 1967. (1968)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 40 (1968), S. 800-806 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Durch einen Vergleich der Ausbreitungscharakteristik von isothermen Drallstrahlen mit den entsprechenden Drallflammen sollte untersucht werden, wie weit sich die für die isothermen Strahlen geltenden Gesetzmäßigkeiten auf frei brennende und eingeschlossene Drallflammen anwenden lassen. Die Versuche zeigten, daß sich die Strömungs- und Konzentrationsfelder ähnlich sind, und daß die bei den Drallflammen auftretenden Änderungen durch die veränderten Umgebungsbedingungen erfaßt werden können. Die Unterschiede zwischen frei brennenden und eingeschlossenen Flammen sind geringfügig, sie lassen sich im wesentlichen auf die Begrenzung der Verbrennungsluft im Feuerraum zurückführen.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330401606
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  • 9
    Electronic Resource
    Electronic Resource
    Maintenance of periportal and pericentral oxygen tensions in primary rat hepatocyte cultures: Influence on cellular DNA and protein content monitored by flow cytometry (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 133 (1987), S. 297-304 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Primary hepatocytes were cultured at oxygen tensions similar to those reported to be present in periportal (13% O2) and pericentral (4% O2) regions of the liver lobules. Cellular DNA and protein content of individual hepatocytes were determined simultaneously by two-parameter (DNA/protein) flow cytometry after 1, 4, and 7 days in culture. PO2 tensions monitored on line in conventional plastic culture dishes revealed that the depletion of the PO2 in the culture medium depended on the number of hepatocytes plated. When cultured as monolayer after 4-7 days at periportal (13% O2) and more pronounced at pericentral oxygen concentration (4% O2), up to 90% of the hepatocytes showed degenerated nuclei but normal protein content. By using culture dishes with teflon membrane bottoms the oxygen tension in the culture medium was accurately maintained by the incubator atmosphere. At pericentral oxygen tension the fraction of 2N cells increased by about 20%. That of the 4N cell was not affected, and the contribution of 8N hepatocytes dropped to 70% compared to cultures at periportal oxygen tension. Concomitantly, in the 4% O2 hepatocyte cultures the protein content of the 2N and the 4N cells was better preserved and increased by up to 10%. These results suggest that in vitro at pericentral oxygen conditions (4% O2) ageing of hepatocytes is delayed, regenerating processes are better maintained, and, furthermore, freshly isolated 4N hepatocytes have the potency to adapt their metabolism in vitro to periportal as well as to perivenous oxygen tensions.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041330213
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  • 10
    Electronic Resource
    Electronic Resource
    Physiological oxygen tension modulates the chemically induced mitogenic response of cultured rat hepatocytes (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 156 (1993), S. 119-129 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Freshly isolated rat hepatocytes were cultured at periportal- (13% O2) or perivenous-like (4% O2) oxygen tension and exposed to subtoxic exposure levels of cyproterone acetate (CPA: 10-330 μM), phenobarbital (PB: 0.75-6 mM), and dimethylsulfoxide (DMSO: 0.1-3.3%) from 24-72 h after seeding. Induced alterations in ploidy, in the number of S-phase cells, the degree of binuclearity, and cellular protein content were determined by twin parameter protein/DNA flow cytometry analysis of intact cells and isolated nuclei. CPA and PB increased whereas DMSO decreased dose dependently the total number of S-phase cells. The changes differed within individual ploidy classes and were modulated by the oxygen tension. CPA increased and DMSO decreased the number of S-phase cells preferentially among the diploid hepatocytes at periportal-like oxygen tension. In contrast, PB increased binuclearity and S-phase cells mainly among the tetraploid hepatocytes at perivenous-like oxygen tension. Cellular protein content increased dose dependently after exposure to the hepatomitogens (CPA, PB) and decreased after exposure to DMSO at both oxygen tensions. Comparison with in vitro data proves that chemicals which interact with cells from the progenitor liver compartment (CPA, DMSO) exert their mitogenic activity best in cultures at periportal-like oxygen tension preferentially in diploid hepatocytes, whereas chemicals which affect cells from the functional compartment show a higher activity at perivenous-like oxygen tension. Physiological oxygen tension seems to be an effective modulator of the proliferative response of cultured rat hepatocytes similar to that expected for periportally or perivenously derived hepatocytes. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041560117
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