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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Astrophysics and space science 255 (1997), S. 91-101 
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Many nearby main sequence stars are surrounded by cool dust radiating strongly in the far-IR. The characteristics of some of the prototype systems will be discussed. The dust is understood to represent debris related to planet formation, and the known disk systems may be dense analogs of the Kuiper Belt structure in our outer solar system. ISO observing programs plan to address questions regarding how common planetary material is around normal stars and how its amount and location depend on system age. These questions are central to an understanding of the place of the "Vega/β Pic" disks in stellar evolution. Preliminary results from the first year of ISO operation will be reported.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of sol gel science and technology 8 (1997), S. 195-199 
    ISSN: 1573-4846
    Schlagwort(e): alumina gel ; surfactant ; mesophase ; template ; porous texture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract This work deals with the synthesis of alumina gels from aqueous solutions of aluminum chloride in the presence of cationic surfactant molecules. The effect on the sol-gel transition of the reagent concentrations and of the synthesis temperature are first studied. The structure of the resulting wet and dried gels and the formation of liquid crystal mesophases are studied by X-ray diffraction. The thermal and structural evolutions of the gels are then characterized by thermogravimetric and X-ray diffraction measurements. Finally, nitrogen adsorption isotherms are used to investigate the porous texture of the thermally treated materials up to the transformation into α-Al2O3.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    World journal of microbiology and biotechnology 4 (1988), S. 221-225 
    ISSN: 1573-0972
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Beschreibung / Inhaltsverzeichnis: Résumé Une souche deZymomonas sp., tolérante à l'éthanol, isolée d'un moût spontanné de canne à sucre, a été testée pour sa faculté de produire de l'éthanol en milieu non renouvelé, à l'état libre ou à l'état immobilisé dans la pectine. On s'est servi du CaCl2 pour la préparation des billes. Le CaCl2 a également été ajouté au milieu de fermentation pour améliorer la stabilité des billes. Tant l'immobilisation que la présence du CaCl2 au delà de 1 g par litre inhibent la fermentation jusqu'à un certain point. Mais le fait que les billes deZymomonas dans le pectine conservaient leur capacité fermentative et leur stabilité mécanique pendant environ 40 fermentations successives en milieu non renouvelé, ouvre la possibilité de les utiliser néanmoins en production continue d'éthanol. On discute aussi le rôle dans la fermentation des cellules libres ainsi que l'effet de la préincubation des billes.
    Kurzfassung: Resumen Una cepa deZymomonas alcohol tolerante, aislada de jugo de caña de azúcar en fermentación espontánea, fue utilizada para ensayos de producción en lote de etanol, tanto libre como inmovilizada en pectina. En este último caso se utilizó CaCl2 en la preparación de las perlas como así también como componente del medio de fermentación, con el objeto de aumentar la estabilidad de las perlas. Los resultados obtenidos indican que tanto la inmovilización como una concentración de Cl2Ca en el medio superior a 1 g/l perjudicaron en cierto grado la fermentación. Las perlas deZymomonas-pectina mantuvieron la actividad fermentativa y estabílidad mecánica durante 40 fermentaciones en lote sucesivas, abriendo la posibilidad de su utilización en la producción continua de etanol. También se analiza la influencia sobre la fermentación de las células libres y de la preincubación de las perlas.
    Notizen: Summary AZymomonas sp strain, alcohol tolerant, isolated from spontaneously fermenting sugarcane juice, was tested for the production of ethanol in batch, free and immobilized in pectin. CaCl2 was used during the preparation of the beads and also added to the fermentation medium to improve the stability of the beads. It was found that immmobilization, as well as CaCl2 above 1 gl−1 impaired fermentation to some extent. As theZymomonas-pectin beads maintained their fermentative capacity and mechanical stability during about 40 successive batch fermentations, this opens up the possibility of using them for the continuous production of ethanol. The role of free cells as well as the effect of the preincubation of the beads on fermentation are also discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    ISSN: 1573-0972
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Beschreibung / Inhaltsverzeichnis: Résumé Une souche floculante deSaccharomyces isolée du jus de canne à sucre a été utilisée pour produire l'éthanol, dans un réacteur continu à flux ascendant, par fermentation de milieux de culture de différentes compositions. Les meilleurs résultats ont été obtenus avec le jus de canne à sucre et les molasses. Les différences qu'on a vues selon le moût utilisé peuvent être dues à l'influence de la composition du milieu sur la vitesse de multiplication et la capacité floculante de la levure, donnant une modification de la concentration de biomasse dans le réacteur.
    Kurzfassung: Resumen Una cepa floculante deSaccharomyces, aislada de jugo de caña de azúcar, se utilizó para producir etanol fermentando medios de distinta composición en un reactor continuo de flujo ascendente. Los mejores resultados se obtuvieron con jugo de caña de azúcar y con melaza. Las diferencias observadas según el mosto utilizado pueden deberse a la influencia de la composición del medio sobre la velocidad de multiplicación y capacidad foculante de la levadura, modificando de esta manera la concentración de biomasa dentro del reactor.
    Notizen: Summary A flocculentSaccharomyces sp., isolated from spontaneously fermenting sugar-cane juice, was used to produce ethanol in a continuous upflow reactor. Media of different composition were tested using the same fermentation conditions. The best results were obtained fermenting either sugar-cane juice or molasses. The differences observed could be due to the influence of the medium composition on the growth rate and on the expression of the flocculent capacity of the yeast, both factors which modified the cell biomass concentration within the reactor.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1573-675X
    Schlagwort(e): Bax ; cell type-specific ; p53 ; reverse transcription-PCR.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Overexpression of the normal p53 protein in tumor cell lines is known to induce apoptosis and a potential mediator of this response is the apoptotic inducer, Bax. The expression of Bax mRNA products were investigated in the ECV-304 endothelial cell tumor line and primary human umbilical vein endothelial cells (HUVEC) that were induced to overexpress the p53 protein. Induction of p53 in ECV-304 and HUVEC cells was mediated by infection with a p53 recombinant adenovirus (AdCMV-p53). The expression of Bax transcripts in p53-induced cells was investigated by reverse-transcription polymerase chain reaction (RT-PCR). The Baxα mRNA species was detected in both ECV-304 and HUVEC cells. Surprisingly, Baxα expression was reduced several-fold in ECV-304 endothelial cells overproducing p53 and no change in Baxα was detected in HUVEC cells after induction of p53. However, the Baxδ spliced transcript was observed to be induced by p53 in the ECV-304 tumor cell line. Baxα was the predominant species expressed in normal human endothelial cells but, in contrast to the immortalized ECV-304 endothelial cell line, induction of p53 failed to alter the expression of Baxα or to induce any other Bax transcripts. HUVEC cells were more resistant to p53, since at least 80% of the HUVEC cell population survived the overexpression of p53 after 24 h of infection with AdCMV-p53. An ECV-304-derived cell line (DECV) resistant to p53-mediated apoptosis did not show any changes in expression of Bax mRNA products, even in the presence of high levels of p53. ECV-304 endothelial cells that expressed the Baxδ species underwent apoptosis much more rapidly and more extensively after induction of p53, suggesting that the Baxδ species enhances p53-mediated apoptosis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    ISSN: 1573-675X
    Schlagwort(e): Apoptosis ; endothelial ; p53
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Transfection of the wild-type p53 gene into an immortalized human endothelial cell line (ECV-304) by recombinant adenoviral delivery resulted in high level expression of the wild-type p53 protein and induction of apoptosis. Increases in the number of apoptotic cells were observed within 12 h after infection of ECV-304 cells with recombinant p53 adenovirus, as deter-mined by the appearance of internucleosomal DNA fragmentation ladders and by TUNEL and electron microscopic analyses. Control cells infected with a β-galactosidase recombinant adenovirus exhibited little or no increase in apoptosis over uninfected cells. The expression of Waf-1 and Bax gene products were in-creased substantially in apoptotic ECV-304 cells as determined by Northern blot, reverse transcription-PCR and immunoblotting analyses. Lesser increases in the expression of the PCNA gene were detected in ECV-304 cells undergoing apoptosis. Both control and apoptotic ECV-304 cells did not express detectable levels of Bcl-2 mRNA or protein in Northern blotting and immunoblotting analyses, respectively. The data suggest a role for the Bax gene product in p53-mediated apoptosis of endothelial cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    ISSN: 1573-675X
    Schlagwort(e): Apoptosis ; non-small cell lung carcinoma ; p53 ; phosphorylation.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The natural metabolic byproduct of estradiol, 2-methoxyestradiol (2-MeOE2), induces apoptosis in human lung cancer cells by a p53-dependent mechanism. The expression of wild-type p53 isoforms was investigated in H1299 non-small cell lung carcinoma cells induced into apoptosis by 2-MeOE2. H1299 cells lack endogenous p53 and undergo predominantly a G1 arrest when infected with a recombinant wild-type p53 adenovirus. However, when H1299 cells transfected with p53 were treated with 2-MeOE2, they underwent rapid and extensive apoptosis. H1299 cells expressing mutant his273 p53 were unaffected by 2-MeOE2, indicating a dependence of 2-MeOE2-mediated apoptosis on the presence of a functional p53. Analysis of wild-type p53 phosphoisoforms in H1299 cells by two-dimensional gel electrophoresis revealed that 2-MeOE2 induced a unique group of acidic p53 isoforms. Although most of the wild-type p53 in untreated H1299 cells migrated as at least five diffuse species with isoelectric points from pH 5.5–6.3, as many as nine additional forms migrating toward the acidic region with pI values from 4.4–5.3 were detected in 2-MeOE2-treated apoptotic cells. Two other agents known to induce apoptosis, vinblastine and actinomycin D, induced a similar pattern of acidic p53 species as that observed for 2-MeOE2. The results indicated that the induction of apoptosis in H1299 cells by 2-MeOE2 is dependent on the upregulation of specific p53 isoforms. Identification of the specific p53 phosphoisoforms induced by MeOE2 will be an important step in understanding the regulation and function of p53 in apoptosis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Journal of sol gel science and technology 2 (1994), S. 25-28 
    ISSN: 1573-4846
    Schlagwort(e): non-hydrolytic gelation ; gelation mechanism ; alumina gel ; mullite ; chloroalkoxides
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Monolithic alumina and aluminosilicate gels have been prepared using a novel sol-gel process based on the non-hydrolytic condensation reaction between a metal halide and a metal alkoxide. XRD indicated that the alumina gel remained amorphous at 750°C; solid state 27Al NMR indicated the presence in the dried gel and in the amorphous calcined sample of a large amount of pentacoordinated aluminum atoms. A study of the sol formation using liquid state 27Al NMR suggested that the gel structure was reminiscent of the oligomeric structure of the chloroisopropoxide precursors. Differential thermal analysis and XRD indicated that the aluminosilicate gels were converted to mullite below 1000°C, suggesting a high degree of homogeneity in these precursors.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 2011-06-03
    Beschreibung: We investigated the changes in faunal activities as measures of the ecological functions of soils impacted by potentially toxic metals (PTMs) under urban, industrial, agricultural, and natural uses. Concentrations and distributions of Zn, Cd, Pb, Cu, Mn, and Fe were estimated by sequential chemical extractions, while relicts and present faunal activities were studied by micromorphological analyses. Urban and natural lands were contaminated with Pb, Cd, and Zn. Microarthropods and fungi are observed to be active in the litter decomposition in natural, agricultural and urban lands which indicates that total concentration of PTMs in soils is not a good indicator to evaluate the limitations of PTMs to fauna activity. Metals immobilization on carbonates and Fe/Mn oxides, and fertilizations reduced the negative effects of metals on faunal activity. Micromorphological analyses showed the impacts of metal on soil ecological functions in industrial site, where the surface soils are devoid of any evidence of faunal activity; likely due to high proportion of Pb and Zn in organic components. Therefore, the impacts of metals in soil fauna activities, hence ecological functions of soils, are best evaluated by the knowledge of metal partitioning on solid phases in combination with observations of fauna activities using micromorphological techniques.
    Print ISSN: 1687-7667
    Digitale ISSN: 1687-7675
    Thema: Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Publiziert von Hindawi
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
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