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  • 1995-1999
  • 1985-1989  (12)
  • 1980-1984
  • 1989  (12)
  • 1
    Electronic Resource
    Electronic Resource
    Lophirones D and E: Two New Cleaved Biflavonoids from Lophira lanceolata (1989)
    s.l. : American Chemical Society
    Journal of natural products 52 (1989), S. 284-288 
    Details
    ISSN: 1520-6025
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/np50062a011
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  • 2
    Electronic Resource
    Electronic Resource
    Transport and utilization of α-ketoglutarate by the rat kidney in vivo (1989)
    Springer
    Pflügers Archiv 413 (1989), S. 217-224 
    Details
    ISSN: 1432-2013
    Keywords: Rat ; Kidney ; Uptake ; Transport ; α-Ketoglutarate ; Luminal ; Basolateral ; Production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In order to establish the characteristics of net renal transport and utilization of α-ketoglutarate (α-KG) in the rat, we have precisely quantified the renal blood flow, the urinary flow and the rates of α-KG delivery, filtration, reabsorption or secretion, excretion, uptake or production by an in vivo rat kidney preparation. In normal rats, α-KG uptake was higher than α-KG reabsorption at both endogenous and elevated plasma α-KG concentrations; thus, a net peritubular transport, which was the main supplier of α-KG to the renal cells, took place. Saturation of reabsorption and peritubular transport of α-KG occurred at blood α-KG concentrations about 30 and 150 times above normal, respectively. Acute metabolic acidosis was found to have no effect on renal handling of α-KG. At endogenous plasma α-KG concentrations, alkalosis converted net renal uptake into net renal production of α-KG resulting in addition of α-KG by the renal cells both to blood and to the luminal fluid. Elevation of blood α-KG concentration restored the renal uptake of α-KG. This uptake, which was entirely accounted for by the peritubular transport of α-KG, reached a maximum which was lower than that observed in normal and acidotic rats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00583533
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Thermoanalytical studies on montmorillonite-pirimicarb complexes (1989)
    Springer
    Journal of thermal analysis and calorimetry 35 (1989), S. 1679-1686 
    Details
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mittels TG und DSC Techniken wurde die thermische Zersetzung der Zwischenschichtkomplexe von homoionischen Proben von Montmorillonit mit dem Karbamatinsektizid Pirimicarb (2-Dimethylamino-5,6-dimethylpyrimidin-4-yl-dimethylkarbamat) untersucht. Die Zersetzung der organischen Verbindung wurde mittels IR-Spektroskopie und Röntgendiffraktion verfolgt. Es wurde beobachtet, daß die thermische Zersetzung von Pirimicarb durch Adsorption an dem Ton katalysiert wird. Sowohl die Katalysatorkapazität des Tones als auch die Werte für die Zersetzungsenthalpie hängen von der Art der Zwischenschichtkationen des Montmorillonites ab.
    Abstract: Резюме Методом ТГ и ДСК изуче но термическое разложение прослоис тых комплексов гомоионных образцов монтмориллонита с карбаматпроизводны м инсектицидом пирим икарб (2-диметиламино-5,6-димет илпиримидин-4-ил-димет илкарбамат). Исследов ание прод uктов разложения было пров едено с помощью ИК спе ктроскопии и рентгенофазового а нализа. Найдено, что термичес кое разложение пирим икарба катализируется адсо рбцией его этим минералом. Каталитич еская способность ми нерала и значения энтальпий р азложения зависят от характеристик межсл оевого катиона монтм ориллонита.
    Notes: Abstract The thermal decomposition of the interlayer complexes of homoionic samples of montmorillonite with the carbamate insecticide pirimicarb (2-dimethylamino-5, 6-dimethyl pyrimidin 4-yl-dimethyl carbamate) was studied using TG and DSC techniques. The decomposition of the organic compound was followed by IR spectroscopy and X-ray diffraction. It was observed that the thermal decomposition of pirimicarb is catalyzed by adsorption by the clay. Both the catalytic capacity of the clay and the values of the decomposition enthalpies depend on the characteristics of the interlayer cation of the montmorillonite.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01912942
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  • 4
    Electronic Resource
    Electronic Resource
    Combined clomiphene citrate (CC) and human menopausal gonadotropins (hMG) in a fixed schedule for follicular recruitment during in vitro fertilization: Effects on premature luteinizing hormone (LH) surges (1989)
    Springer
    Journal of assisted reproduction and genetics 6 (1989), S. 121-124 
    Details
    ISSN: 1573-7330
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Recognizing the association between plasma progesterone (P) and an imminent LH surge, we investigated the frequency of P elevation in our stimulation protocol (clomiphene citrate-human menopausal gonadotropins). P was measured retrospectively on the day before, the day of, and the day after human chorionic gonadotropin hCG administration. The means ±2 standard deviations for P were as follows: day before hCG, 0.58±0.86; day of hCG, 0.64 ± 0.56; and day after hCG, 1.47 ± 1.22. Seven patients (8%) had P levels greater than 2 SD above the mean. Significant P elevations prior to hCG are infrequent with this protocol, and in the few patients with raised P a trend toward lowered fertilization was noted. The low incidence of P elevation may be secondary to the administration of hCG in a timely manner on the sixth day of estradiol (E2) rise.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01130741
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  • 5
    Electronic Resource
    Electronic Resource
    Increased human menopausal gonadotropin dose during the early follicular phase: Effect on follicular recruitment and treatment outcome (1989)
    Springer
    Journal of assisted reproduction and genetics 6 (1989), S. 112-117 
    Details
    ISSN: 1573-7330
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To investigate whether the provision of increased gonadotropins would enhance follicular recruitment and selection, women not responding (N=18) to our standard clomiphene citrate (CC)-human menopausal gonadotropin (hMG) regimen were treated with increased hMG (treatment cycle II). Estradiol levels were higher in treatment cycle II and these differences were significant on days 8 and 9 (P≤0.05 andP≤0.03, respectively). On day 9, better follicular development was seen in cycle II (P≤0.05). While none of the patients responded in cycle I, 10 of 18 responded in cycle II. Of the 10 responders, 2 conceived following in vitro fertilization and embryo placement. Increasing the dose of hMG improved the development of a cohort of follicles so that aspiration and possible pregnancy were achieved in women who were previously unresponsive to therapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01130738
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  • 6
    Electronic Resource
    Electronic Resource
    Uniform assessment of success rates with assisted reproductive technology (1989)
    Springer
    Journal of assisted reproduction and genetics 6 (1989), S. 315-316 
    Details
    ISSN: 1573-7330
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01139190
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    Lipid production in wheypermeate by an unsaturated fatty acid mutant of the oleaginous yeastApiotrichum curvatum (1989)
    Springer
    Biotechnology letters 11 (1989), S. 477-482 
    Details
    ISSN: 1573-6776
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Growth rate and lipid production rate of an unsaturated fatty acid mutant (Ufa25), derived from the oleaginous yeastApiotrichum curvatum, in wheypermeate supplemented with rapeseed oil (as unsaturated fatty acid source), was comparable with wild type. The quality of the lipids produced by Ufa25 approached cocoa butter. Production of 1 kg lipid by Ufa25 will need about 6.3 kg lactose from whey and 0.5 kg rapeseed oil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01026645
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  • 8
    Electronic Resource
    Electronic Resource
    Recent mathematical approaches to reconstruct phylogenies: A chemosystematist's and botanist's view (1989)
    Springer
    Plant systematics and evolution 168 (1989), S. 109-121 
    Details
    ISSN: 1615-6110
    Keywords: Algae ; bacteria ; Mathematical phylogenetics ; biological relevance ; chemosystematics ; taxonomy ; graph theory ; algorithms ; Steiner problem ; parsimony ; dichotomy ; polytomy ; cytochrome c ; parallelism ; convergent evolution ; Wagner trees ; random distribution ; molecular clock ; identity matrix ; difference matrix ; homology ; analogy ; structural constraints ; comparability of sequences ; polyphyletic hypothesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Some basic problems of mathematical phylogenetics are discussed. While algorithms regularly depend on the principle of parsimony, some features of phylogenesis interfere with that principle. Nonrandomness of the distribution of mutations as well as the inconstancy of the molecular clock in time and within a given sequence can bias the calculated relationships of closely related taxa. True comparability of sequences is difficult to establish, since this requires defining of homology of positions and of functions of amino acids as well. Parallelism and convergence can give rise to errors in establishing homology. Furthermore, they are difficult to be integrated into a consistent mathematical approach. The asymmetry of identity versus difference matrices is discussed. Common mathematical procedures implicate the monophyletic hypothesis as well as strict dichotomy of the final tree. Real phylogeny demands to introduce more flexible approaches with respect to monophyly and dichotomy. Graph theory offers the possibility to prove the minimality of a given tree and to develop more flexible approaches. The consequences of altering the procedures to compare sequences can be tested. This is demonstrated by calculations with a set of 15 cytochromes from various taxa. To interpret a calculated tree requires a sharp distinction between taxonomy and phyletics. This is exemplified for the case of directly linked taxa. The limits of resolving uncertain relationships by accumulating more data are mentioned.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00936092
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  • 9
    Electronic Resource
    Electronic Resource
    Size exclusion chromatography on porous fractals (1989)
    Springer
    Chromatographia 27 (1989), S. 257-263 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Size exclusion ; Fractal dimension ; Retention model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Some porous packings used in chromatography have been claimed to be fractals with a scale of sizes a〈l〈L, where a is a molecular size and L is the size of the largest pores. For a fractal porous packing, the excluded volume for molecules in solution in the vicinity of the packing surface is directly related to Df, the fractal dimension of the pore surface (2〈Df〈3). Since retention in size exclusion chromatography is itself directly related to this excluded volume, the fractal nature of the packing provides a model of retention in this technique. According to this model there is a linear relationship between log Rs and log(1-Kd), where Rs is the hydrodynamic radius of the solute macromolecules and Kd the distribution coefficient. The fractal dimension is derived from the slope of this plot. Size exclusion chromatographic retention data have been analyzed according to the model. It is found that some HPLC packings are fractals with fractal dimensions ranging from about 2.15 to 2.6, depending on the material. Such a large range of Df values indicates large variations in the selectivities and domains of applications of the different packings. For some classical gel filtration chromatographic gels, the fractal retention model does not seem to apply.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02260458
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  • 10
    Electronic Resource
    Electronic Resource
    Failure of spermatozoa from T/t mice to fertilize in vitro is overcome by zona drilling (1989)
    New York, NY : Wiley-Blackwell
    Gamete Research 22 (1989), S. 369-373 
    Details
    ISSN: 0148-7280
    Keywords: assisted fertilization ; t-locus mice ; in vitro fertilization ; infertility ; mouse ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Failure of epididymal spermatozoa from T/t mutant mice, but not from t/t individuals, to fertilize oocytes in vitro was partially overcome by opening a small aperture in the zona pellucida with acidified Tyrode's solution to permit direct access of the spermatozoon to the vitellus. This study provides a model system to evaluate requirements for successful zona drilling in the treatment of human infertility and further insights into the effects of the t complex on sperm fertility.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120220403
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