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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Journal of industrial microbiology and biotechnology 14 (1995), S. 355-364 
    ISSN: 1476-5535
    Schlagwort(e): Transformation ; Fungi ; Yeast ; Genetics ; Biotechnology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Summary The genetic investigation of fungi has been extended substantially by DNA-mediated transformation, providing a supplement to more conventional genetic approaches based upon sexual and parasexual processes. Initial transformation studies with the yeastSaccharomyces cerevisiae provided the model for transformation systems in other fungi with regard to methodology, vector construction and selection strategies. There are, however, certain differences betweenS. cerevisiae and filamentous fungi with regard to type of genomic insertion and the availability of shuttle vectors. Single-site linked insertions are common in yeast due to the high level of homology required for recombination between vectored and genomic sequences, whereas mycelial fungi often show a high frequency of heterologous and unlinked insertions, often in the form of random and multiple-site integrations. While extrachromosomally-maintained or replicative vectors are readily available for use with yeasts, such vectors have been difficult to construct for use with filamentous fungi. The development of vectors for replicative transformation with these fungi awaits further study. It is proposed that replicative vectors may be inherently less efficient for use with mycelial fungi relative to yeasts, since the mycelium, as an extended and semicontinuous network of cells, may delimit an adequate diffusion of the vector carrying the selectable gene, thus leading to a high frequency of abortive or unstable transformants.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 41 (1995), S. 2282-2291 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The low-temperature nitridation of gallium arsenide, silicon and transition metals was investigated using hydrazine. Gallium nitride films were grown on gallium arsenide (GaAs) by direct reaction of the semiconductor surface layers with hydrazine et 200-400°C. Auger electron spectroscopy and X-ray photoelectron spectroscopy (XPS) analyses show that the films are primarily gallium nitride with a small oxide impurity. Thin nitride films (∼15 Å) were grown on silicon by reaction with hydrazine at 300-500°C. Ellipsometry results suggest that the film growth goes through different phases following linear, parabolic and logarithmic functions with time. XPS analysis shows that the nitride films could be formed at much lower temperatures than possible with ammonia (300 vs. 600°C). The formation of numerous transition metal nitrides (Co, Cr, Fe, Mo, Si, Ta, Ti, V, and W) by reaction with hydrazine at 400°C is demonstrated, as well as the chemical vapor deposition of boron nitride films from diborane and hydrazine reactants. The temperature at the mixing point was critical in determining the final composition of the film. A 1-D transport model suggests that the reaction rate at 400°C was kinetically limited. The results also agree qualitatively with thermodynamic equilibrium calculations.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 38 (1992), S. 1092-1104 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: We present an approach for determining in vitro the means and distributions of a set of phenomenological parameters, including cell speed and persistence time, which can be used to evaluate the effect of isotropic variations in the extracellular environment on the motility of human tissue cells. Using time-lapse videomicroscopy and semi-automated image analysis, we tracked the paths traveled by slow-moving, isolated human vascular smooth muscle cells over 48 hours on surfaces of petri dishes coated with 10 μg/mL of the adhesive extracellular matrix proteins type IV collagen, fibronectin or laminin. By applying a persistent random walk model to experimental data for mean-squared displacement as a function of time for these cells, we rigorously distinguished individual cells with different motile characteristics not obvious based on qualitative comparisons between the structures of individual cell paths. We also positively identified the presence of immotile cells. Based on the behavior of 34 to 77 cells on each substrate, we found mean cell speeds and persistence times on the order of 10 micron/h and 3 hours, respectively, on all three ECM substrates, while the fraction of motile cells varied from 65% on laminin to 78% on collagen. On all three surfaces experimental number distributions of speed and persistence time could be described by normal and exponential waiting time distributions, respectively. Our approach provides a framework for addressing questions concerning the mechanistic relationship between cellular and environmental properties and cell motility.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 11 (1965), S. 319-324 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The foam separation process uses differences in surface activity to separate components of a solution. Stable foams can flow upward countercurrent to liquid to give countercurrent differential separations with stripping, enrichment, or scrubbing similar to solvent extraction.Six- and 24-in. I.D. foam columns were operated with sodium dodecylbenzenesulfonate solutions to measure height of transfer unit (HTU) values and foam densities and to develop satisfactory gas spargers, liquid feed distributors, foam drainage conditions, and foam condensation equipment. The HTU values for stripping of Sr-89 were about 1 cm. for the best conditions of uniform foams, liquid flows of 100 gal./sq.ft.hr. or less, and uniform liquid feed distribution with low inlet velocities. Variations of countercurrent column lengths within 10 to 28 cm. caused little variation in HTU values. The foams were condensed, with four types of pneumatic or mechanical foam breakers used. A pilot plant was designed for decontamination of a low level radioactive waste.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 20 (1974), S. 67-73 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A theoretical and experimental investigation of the pumping characteristics of the normal stress extruder was made. The theoretical model requires only material property data and extruder dimensions and rotation speed to evaluate the main velocity field, flow rate, and pressure. The flow from the extruder was measured for two viscoelastic polymer solutions and a polymer melt as a function of gap setting and angular velocity. These measurements were in reasonable agreement with the proposed model.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    ISSN: 1434-193X
    Schlagwort(e): Indiumallyl compounds ; Vinylcyclopropanes ; α,β-Unsaturated carbonyl compounds ; Diastereoselectivity ; Dibenzylideneacetone ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: ---Allylindium reagents, prepared from excess allylic halide (Br or I) and indium metal, react with α,β-unsaturated ketones and aldehydes to give, after aerobic acidic workup, homoallyl-substituted vinylcyclopropanes. This process was explored and developed after a chance discovery arising from a side reaction in an attempted Pd-catalysed process. The structure of the cyclopropane arising from the reaction of bis(p-chlorobenzylidine)acetone was confirmed by X-ray crystallography. Whilst bis-α,β-unsaturated ketones give rise to a single homoallylcyclopropane species, α,β-unsaturated ketones and aldehydes give diastereomeric mixtures whose relative stereochemistry were assigned by NOE experiments. Crotylindium reagents react with good to perfect regioselectivity to afford tetrasubstituted cyclopropanes but prenylindium reagents fail to generate the analogous pentasubstituted rings.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    ISSN: 1434-193X
    Schlagwort(e): Indium ; Vinylcyclopropanes ; Ring closing metathesis ; Norcarenes ; Kinetic diastereoselection ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: ---Homoallyl-substituted vinyl cyclopropanes 1a-c, which are readily prepared by reaction of allylindium reagents with α,β-unsaturated ketones and aldehydes, undergo Ru-catalysed RCM reactions with Grubbs catalyst to give [4.1.0]bicyclooct-2-ene (norcarene) type bicyclic products. Noncyclisable ‘trans’ homoallyl-substituted vinyl cyclopropanes 1b and 1c are separated from their ‘cis’ diastereomers by RCM to 5b and 5c - but only with moderate efficiency due to a competing homo-cross metathesis (‘dimerisation’) to give 7b and 7c, respectively. However, the four diastereomers of the (homoallyl)distyrylcyclopropane 14a obtained from indium-mediated reaction of dibenzylideneacetone and crotyl bromide undergo remarkable kinetic diastereoselection in their RCM reactions to give a 4,7-dimethyl[4.1.0]bicyclohept-2-ene-type product 15a. This process allows recovery of a single diastereomer (〉 95%) of 14a without dimerisation being a significant side reaction. Furthermore, the RCM product 15a is obtained rich in one diastereomer (ca. 90%). The kinetic diastereoselection and lack of dimerisation can be rationalised by considering developing transannular interactions and a pseudo-A1,3 strain model.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 7 (1961), S. 80-86 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Methods for expressing, measuring, and correlating drop-size distribution data for centrifugal spray nozzles are discussed.A method for collecting spray droplets in liquid nitrogen is described which is rapid and efficient for most sprayed liquids which freeze above  - 20°C. Comprehensive correlations for drop-size distributions are reported based on 114 runs performed with the liquid nitogen method.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 21 (1975), S. 383-385 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    ISSN: 1434-1948
    Schlagwort(e): Chirality ; Ruthenium ; Chiral resolution ; Nitrogen heterocycles ; Carbonyl complexes ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A range of chiral building blocks of the type Δ- or Λ-[Ru(pp)2(CO)2]2+ {pp = bidentate ligands bpy (2,2′-bipyridine), phen (1,10-phenanthroline) and Me2bpy (4,4′-dimethyl-2,2′-bipyridine)} have been synthesized, and their enantiomeric purity and absolute configurations determined by CD and NMR studies. Decarbonylation using trimethylamine oxide in the presence of the respective pp ligand at room temperature produced the corresponding tris(bidentate) species [Ru(pp)3]2+ with retention of configuration at the ruthenium(II) centre. A general chromatographic technique for resolution of tris-homoleptic complexes of the type [Ru(pp)3]2+ was investigated, with the absolute configurations of the resolved complexes confirmed by CD studies, and the X-ray structural analyses of Δ-(-)-[Ru(Me2bpy)3]{(-)-O,O′-dibenzoyl-L-tartrate} and Λ-(+)-[Ru(phen)3]{(+)-O,O′-di-4-toluoyl-D-tartrate}. Resolution is also reported for the analogous species containing three potential bridging ligands, [Ru(bpm)3]2+ and [Ru(HAT)3]2+ (bpm = 2,2′-bipyrimidine; HAT = 1,4,5,8,9,12-hexaazatriphenylene). The versatility of the chromatographic procedure was demonstrated by the resolution of a series of bis-heteroleptic complexes [Ru(pp)2(pp′)]2+ {pp′ = dpq (dipyrido[3,2-d:2,3′-f]quinoxaline), dpqc (dipyrido[3,2-a:2,3-d]-6,7,8,9-tetrahydrophenazine), and dppz {dipyrido[3,2-a:2,3′-d]phenazine)}.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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