ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Transmission electron microscopy study of CdTe(111) grown on GaAs(100) by molecular-beam epitaxy (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 4114-4117 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have used transmission electron microscopy to investigate CdTe(111) grown on GaAs(100) by molecular-beam epitaxy. The loop structure previously observed by photoluminescence microscopy has been identified as the boundary between twinned microcrystallites that extend from the CdTe/GaAs interface to the CdTe surface. When viewed along the growth axis, these boundaries between the columnar twins appear as loops and segments. Surface roughness of the GaAs substrate contributes to the initial growth of twinned material. This leads to competitive growth between the twins and the creation of the observed columnar twins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.344971
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    NMR studies of multiple conformations in complexes of Lactobacillus casei dihydrofolate reductase with analogs of pyrimethamine (1990)
    s.l. : American Chemical Society
    Biochemistry 29 (1990), S. 9660-9667 
    Details
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/bi00493a022
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Dihydrofolate reductase; sequential resonance assignments using 2D and 3D NMR and secondary structure determination in solution (1991)
    s.l. : American Chemical Society
    Biochemistry 30 (1991), S. 6330-6341 
    Details
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/bi00239a035
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The Platanar-Aguas Zarcas volcanic centers, Costa Rica: spatial-temporal association of Quaternary calc-alkaline and alkaline volcanism (1993)
    Springer
    Bulletin of volcanology 55 (1993), S. 443-453 
    Details
    ISSN: 1432-0819
    Keywords: Arc volcano ; magma mixing ; geochemistry ; alkaline ; calc-alkaline ; sector collapse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The Platanar volcanic center is dominated by a calc-alkaline, basalt-andesite-dacite-rhyolite magma series with unusual LREE enrichment. Adjacent and overlapping the calc-alkaline rocks are the most alkaline basalts found along the volcanic front of Central America. These basalts are mafic, LIL- and LREE-enriched transitional to alkaline basalts. Several are found on the north flank of Platanar in the Aguas Zarcas region, where there are nine cinder cones and a few isolated flows. However, they are also found in isolated lava outcrops at least as far south as Porvenir volcano along the volcanic front. The addition of mafic alkaline magmas with high La/Yb and low Ba/La into the Platanar magma chamber or chambers may contribute to the LREE-enriched character of the Platanar basaltic andesites and andesites. At Platanar the field and geochemical evidence suggest mixing between calc-alkaline and alkaline magmas, a process that has probably occurred throughout the development of the Cordillera Central of Costa Rica. The presence of negative Ce anomalies in several of the calc-alkaline lavas also make the Platanar complex very unusual compared to the rest of the Central American volcanic front. In the center of the Platanar complex is the Chocosuela caldera, an apparent remnant of an avalanche caldera created by the collapse in the Middle Pleistocene of an ancestral stratovolcano toward the NNW in a directed blast-type eruption. Rhyolite is present as pumice lapilli in pyroclastic flow deposits outside the caldera rim. Whole lapilli analyses span the daciterhyolite range. The previous eruption of high silica tephra as pyroclastic flows, the current long dormant period and the repeated occurrence of earthquake swarms on the flanks of the Platanar complex make it a candidate for volcanic hazard mapping, detailed geological mapping and emergency planning.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00302004
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Incompatible element and isotopic evidence for tectonic control of source mixing and melt extraction along the Central American arc (1990)
    Springer
    Contributions to mineralogy and petrology 105 (1990), S. 369-380 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The Sr and Nd isotopic ratios of Central American volcanics can be described by the mixing of four components, marine sediment from DSDP Site 495, MORB-source mantle (DM), EMORB-source mantle (EM), and continental crust. Most of the isotopic data define a trend between EM and a modified mantle (MM) formed as a mixture of DM and less than 0.5% marine sediment, or fluid derived there from. The MM to EM trend is equally apparent in the incompatible-element data and is most clearly seen in a Ba/La versus La/Yb plot. A hyperbolic trend connects high Ba/La and low La/Yb at the MM end of the trend to low Ba/La and high La/Yb at the EM end. Smooth regional variations in incompatible-element and isotopic ratios correlate with the dip of the subducted slab beneath the volcanic front and the volume of lava erupted during the last 100,000 years (volcanic flux). Steep dip and low flux characterize the MM end-member and shallow dip and high flux characterize the EM end-member. The simplest model to explain the linked tectonic and geochemical data involves melting in the wedge by two distinct mechanisms, followed by mixing between the two magmas. In one case, EM magma is generated by decompression of EM plus DM asthenosphere, which is drawn in and up toward the wedge corner. EM mantle is preferentially melted to small degrees because of the presence of low melting components. The second melt is formed by release of fluid from the subducted slab beneath the volcanic front to form MM magma. Mixing between EM and MM magmas is controlled by subduction angle, which facilitates delivery of EM magma to the volcanic front at low-dip angles and impedes it at steep-dip angles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00286825
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    3D 13C/1H NMR-based assignments for side-chain resonances of Lactobacillus casei dihydrofolate reductase. Evidence for similarities between the solution and crystal structures of the enzyme (1993)
    Springer
    Journal of biomolecular NMR 3 (1993), S. 535-546 
    Details
    ISSN: 1573-5001
    Keywords: Dihydrofolate reductase ; NMR ; 13C/15N labelled protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary 13C-based three-dimensional 1H−1H correlation experiments have been used to determine essentially complete 13C and 1H resonance assignments for the amino acid side chains of uniformly 13C/15N labelled L. casei dihydrofolate reductase in a complex with the drug methotrexate. Excellent agreement is observed between these assignments and an earlier set of partial assignments made on the basis of correlating nuclear Overhauser effect and crystal structure data, indicating that the tertiary structure of the enzyme is similar in solution and in the crystal state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00174608
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Histochemistry and morphology of porcine mast cells (1993)
    Springer
    Journal of molecular histology 25 (1993), S. 516-522 
    Details
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Mast cells have been described extensively in rodents and humans but not in pigs, and the objective of this study was to characterize porcine mast cells by histochemistry and electron microscopy. Carnoy's fluid proved to be a good fixative but fixation with neutral buffered formalin blocked staining of most mast cells. Alcian Blue stained more mast cells than did Toluidine Blue (pH 0.5), although Alcian Blue also stained goblet cells. In pigs, unlike rodents, the Alcian Blue method did not distinguish between mast cells in the intestinal mucosa and those in the connective tissue of the intestinal submucosa, tongue and skin. Mast cells were significantly larger in adult pigs than in piglets; in adult pigs and piglets, mast cells in the intestinal mucosa were significantly larger than those in submucosal connective tissue, and they were more varied in shape in piglets and adults. Granules in mast cells in the intestinal mucosa stained less intensely than those in mast cells in connective tissue of tongue, skin and intestinal submucosa. Mast cells in the connective tissue of the tongue, skin and intestinal submucosa fluoresced strongly when stained with berberine sulphate or with a mixture of berberine sulphate and Acridine Orange, but mast cells in the intestinal mucosa did not. All mast cells reacted positively in an enzyme-histochemical method previously used to detect human tryptase but not in a method previously used to detect human chymase. Mast cells in the medulla of thymus stained similarly to mast cells in the intestinal mucosa. Ultrastructural differences between mast cells were not detected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00159288
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Starch-derived glycol and glycerol glucosides prepared by reactive extrusion processing (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 45-53 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Previously, starch-derived glycol and glycerol glucosides were prepared by batch-reaction processes and had excellent potential as chemical intermediates for a wide range of products. However, more efficient processes for preparation of these derivatives are needed. In this present work, a modern corotating, intermeshing, twin-screw extruder with a barrel length/screw diameter (L/D) ratio of 43: 1 was used to study the reaction of starch with ethylene glycol and glycerol in the presence of sulfuric acid catalyst at elevated temperatures. A fully continuous process was used. Variables that were investigated included temperature (140-180°C), glycol or glycerol/starch AGU mol ratio (1.5-4.0), starch feed rate (5-30 lb/h), screw speed (100-475 rpm), residence time, specific energy, and several types of commercial cornstarch and corn flour products. Rates and extents of reaction that occurred in the barrel were determined by analyzing samples that were quenched just prior to extrusion. The major glucosides were quentitated by high-performance liquid chromatography. Results of this study show that starch can be continuously, rapidly, and efficiently converted to glucosides in 90% yield at high production rates. Such processing is expected to be technically feasible for the reaction of a wide range of polyhydroxy alcohols with various starch substrates.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070420106
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Preparation and properties of rigid polyurethane foams containing modified cornstarches (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 44 (1992), S. 1477-1483 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Rigid polyurethane foams were prepared containing 20% (based on weight of polyol) unmodfied or modified cornstarches. The cornstarches had been modified by breeding or conversion methods and included waxy, acid-modified waxy, malto-dextrin, and canary dextrin. Due to its more favorable role as an extender, canary dextrin was added to additional foam formulations at 10-40%. Foams containing dextrins responded to compressive stress as control foams with yield points before 10% deformation. Foams filled with the unmodified or waxy cornstarches did not give clearly defined yield points and were measured at 10% deformation. After 14 days under 70°C and ambient conditions, volume increases for the filled foams were 4.0-7.1% vs. 4.6% for the control. The foams filled with canary dextrin increased in volume 4.3%. With the addition of 40% canary dextrin, the volume increases for the foams were 4.4% under thermal conditions and 4.5% under humid conditions (38°C and 98% relative humidity). Under humid conditions for 14 days, the foams containing canary dextrin increased in weight as dextrin content increased (1.5, 3.2, 3.4, and 7.6% with 10, 20, 30, and 40% dextrin, respectively). with 40% canary dextrin in the foams, thermal conductivity was 0.0235 vs. 0.0242 W/mK (0.163 vs. 0.168 Btu in/ft2h°F) for the control.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070440818
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Preparation of cationic starch containing quaternary ammonium substituents by reactive twin-screw extrusion processingThe mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned. (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 54 (1994), S. 1855-1861 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Cationic starch, an important additive for papermaking and other uses, was prepared from native cornstarch and 3-chloro-2-hydroxypropyltrimethylammonium chloride in aqueous sodium hydroxide using a twin-screw extruder as the reactor. The effects of physical and chemical reaction variables on reaction efficiency (RE) and degree of substitution (DS) of up to 0.05 were studied. RE was based on nitrogen content contributed by cationization of the starch after the products were exhaustively washed to remove unreacted monomer. Under certain reaction conditions, exceptionally high RE (90%+) was achieved, exceeding maximum values previously reported using laboratory-batch reaction procedures. The combined effects of high reaction temperature (90°C), intense mixing, high-starch solids (65%), and appropriate levels of catalyst contributed to the unusually high RE values achieved by the reactive extrusion process. © 1994 John Wiley & Sons, Inc.†
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070541208
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...