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  • 1
    Electronic Resource
    Electronic Resource
    Biotechniques for improving acid aluminum tolerance in alfalfa (1993)
    Springer
    Plant cell reports 12 (1993), S. 590-592 
    Details
    ISSN: 1432-203X
    Keywords: Alfalfa ; Media ; Callus ; fresh weight
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Alfalfa (Medicago sativa L.), cultivars ARC, Regen Y and Saranac were selected in vitro in a recently developed acid/aluminum toxic media. The new media produced higher initiation rates and higher fresh callus weights than those obtainable with the media described by Meredith and Connor for the selection of aluminum resistant variants in Nicotiana plumbaginofolia. Both rescue and direct initiation yielded adequate amounts of healthy callus for the initiation of embryogenesis. The toxic effect of the acid/aluminum media is expressed in both the percent of explants initiating callus and in the fresh-weights obtained during initiation and two subsequent subcultures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233067
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  • 2
    Electronic Resource
    Electronic Resource
    The combination of molecular dynamics with crystallography for elucidating protein–ligand interactions: a case study involving peanut lectin complexes with T-antigen and lactose (2001)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 57 (2001), S. 1584-1594 
    Details
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Peanut lectin binds T-antigen [Galβ(1–3)GalNAc] with an order of magnitude higher affinity than it binds the disaccharide lactose. The crystal structures of the two complexes indicate that the higher affinity for T-antigen is generated by two water bridges involving the acetamido group. Fresh calorimetric measurements on the two complexes have been carried out in the temperature range 280–313 K. Four sets of nanosecond molecular-dynamics (MD) simulations, two at 293 K and the other two at 313 K, were performed on each of the two complexes. At each temperature, two somewhat different protocols were used to hydrate the complex in the two runs. Two MD runs under slightly different conditions for each complex served to assess the reliability of the approach for exploring protein–ligand interactions. Enthalpies based on static calculations and on MD simulations favour complexation involving T-antigen. The simulations also brought to light ensembles of direct and water-mediated protein–sugar interactions in both the cases. These ensembles provide a qualitative explanation for the temperature dependence of the thermodynamic parameters of peanut lectin–T-antigen interaction and for the results of one of the two mutational studies on the lectin. They also support the earlier conclusion that the increased affinity of peanut lectin for T-antigen compared with that for lactose is primarily caused by additional water bridges involving the acetamido group. The calculations provide a rationale for the observed sugar-binding affinity of one of the two available mutants. Detailed examination of the calculations point to the need for exercising caution in interpreting results of MD simulations: while long simulations are not possible owing to computational reasons, it is desirable to carry out several short simulations with somewhat different initial conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0907444901011957
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  • 3
    Electronic Resource
    Electronic Resource
    Structural and optical properties of Bi x Se1−x films (1992)
    Springer
    Journal of materials science 3 (1992), S. 164-167 
    Details
    ISSN: 1573-482X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Bi x Se1−x thin films have been studied because of their structural and optical properties with a view to judging their suitability as the recording medium in phase-change type optical recording. Amorphous films deposited at room temperature were crystallized by thermal annealing. X-ray diffraction analysis and surface morphological studies are reported. A maximum reflectivity difference of 25% at λ=830 nm was obtained upon amorphous-to-crystalline transition. The optical constants calculated by the Newton-Raphson method using the experimental transmittance, reflectance and thickness data are reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00695514
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  • 4
    Electronic Resource
    Electronic Resource
    Thermal and optical properties of Ge5Bi18Se77 films (2000)
    Springer
    Journal of materials science 11 (2000), S. 397-400 
    Details
    ISSN: 1573-482X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Amorphous films of Ge5Bi18Se77 deposited by vacuum evaporation have been studied for their thermal and optical properties. Differential scanning calorimetry (DSC) has been used to perform the thermal analysis to estimate the activation energy for crystallization (Ec) and the order of crystallization (m) of this material. The high value of (Ec), 1.672 eV, indicates good stability of the amorphous phase. The optical constants of the as-deposited, amorphous and the thermally annealed crystalline films indicate semiconducting behavior and the band gap (Eg) determined from Tauc's plot are 0.92 eV and 0.8 eV for the amorphous and crystalline films, respectively. The value of the absorption coefficient (α) is of the order of 104cm-1 in the optical range for both amorphous and crystalline films. The studies on optical and thermal properties confirm the suitability of these firms in phase change optical recording.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008958903218
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  • 5
    Electronic Resource
    Electronic Resource
    Study of surface topography and optical properties of Ge15Bi38Se47 films (1998)
    Springer
    Journal of materials science 9 (1998), S. 133-137 
    Details
    ISSN: 1573-482X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Adherent and smooth amorphous GeBiSe films deposited by vacuum evaporation at substrate temperatures less than 30 °C have been studied for their structural and optical properties. The films were crystallized by thermal annealing and they were found to be polycrystalline in nature. A correlation between X-ray diffraction (XRD) data and surface topography is reported. Optical constants calculated from reflectance and transmittance data indicate semiconducting behaviour. The optical band gap of the as-deposited film is 1.0 eV. The measured optical contrast at 0.8 μm is 44%. No significant changes in the optical parameters have been observed after exposing the samples to laboratory ambient for a period of six months. © 1998 Chapman & Hall
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008813506876
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  • 6
    Electronic Resource
    Electronic Resource
    Structural and optical properties of GaGeTe thin films (1991)
    Springer
    Journal of materials science 2 (1991), S. 109-111 
    Details
    ISSN: 1573-482X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Smooth and pinhole-free thin films of Ga5Ge19Te76 have been obtained by vacuum evaporation. The as-deposited films are amorphous. Thermal annealing at 222°C leads to an amorphous-to-crystalline transition. A maximum contrast of 30% in reflectivity (measured at 1 µm) has been obtained on phase transition from amorphous to crystalline state. The optical constants and the bandgap are reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00694761
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  • 7
    Electronic Resource
    Electronic Resource
    Phosphorus removal by ponds receiving polluted water from non-point sources (1993)
    Springer
    Wetlands ecology and management 2 (1993), S. 171-176 
    Details
    ISSN: 1572-9834
    Keywords: Adsorption ; phosphorus removal ; pond ; sediment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phosphorus discharged into the water column of lakes, streams, reservoirs, and ponds is either assimilated by algae or retained by the sediment. A laboratory study was conducted using intact sediment-water columns obtained from three ponds to measure their capacity to assimilate P. Phosphorus retention by these systems was determined at two P levels (2 and 10 mg PL−1 or equivalent to an area loading of 26 and 130 μg cm−2). The potential P removal rates were 20.4, 28.8 and 30.8 μg P CM−2 day−1 for PSF (pond adjacent to septic fields), PP(pond adjacent to a pasture), and PAF (pond adjacent to agricultural farm land), respectively. Longer residence time was needed for P removal at high P loading (10 mg PL−1) than at low P loading (2 mg P L−1). At high P loading, 76–82% of the floodwater P was removed within 10 days. All sediments showed a greater sorption capacity under reduced conditions than under oxidized conditions. At the P levels evaluated, pond sediments functioned as net sinks for water column P.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00188151
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  • 8
    Electronic Resource
    Electronic Resource
    Influence of acid rain and ozone on soil heavy metals under loblolly pine trees: A field study (1995)
    Springer
    Plant and soil 171 (1995), S. 59-62 
    Details
    ISSN: 1573-5036
    Keywords: acid rain ; heavy metals ; loblolly pine ; ozone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A field growth chamber study was conducted to determine the effects of ozone and simulated acid rain (SAR) on soil heavy metals. Loblolly pine (Pinus taeda L.), grown in open-top chambers, was exposed to three concentrations of ozone (charcoal filtered air with 0.026 µL O3 L-1, and two non-filtered treatments in which ozone concentrations were 0.074 µL L-1 and 0.147 µL L-1, respectively) and two levels of SAR (pH 3.5 and 5.2). Ozone was applied for 12 h d-1 for 9 months and acid rain deposition was 125 mm event-1. After 9 months exposure, soil pH, organic matter and DTPA-extractable heavy metals (Cd, Pb, Zn, Mn, Fe, Cu) were determined on soil samples collected from exposed chambers at two depths (0–15 cm and 15–30 cm). Simulated acid rain decreased the original soil pH. The concentrations of Cd, Pb and Mn at SAR pH 3.5 were significantly higher than at SAR pH 5.2. Ozone did not affect Zn, Fe and Cu, but a significant interaction between pH and O3 on Mn, Pb and Cd was observed. Due to the poor drainage capacity of this soil, leaching of heavy metals was not observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00009565
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