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  • ErBa2Cu3O7  (2)
  • Heavy metals  (2)
  • Life and Medical Sciences  (2)
  • Recombinations  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Effect of four heavy metals on the biology of Nostoc muscorum (1990)
    Springer
    BioMetals 2 (1990), S. 229-234 
    Details
    ISSN: 1572-8773
    Keywords: Heavy metals ; Efflux of Na+ and K+ ; Nostoc muscorum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary This study presents the effects of Cr, Pb, Ni and Ag on growth, pigments, protein, DNA, RNA, heterocyst frequency, uptake of NH4 + and N03 −, loss of electrolytes (Na+ and K+), nitrate reductase and glutamine synthetase activities ofNostoc muscorum. The statistical tests revealed a direct positive correlation between the metal concentration and inhibition of different processes. Ni was found to be more toxic against growth, pigments and heterocyst differentiation compared to the other metals. Inhibition of pigment showed the following trend: chlorophyll 〉 phycocyanin 〉 carotenoid. No generalized trend for inhibition of macromolecules was observed. The loss of K+ and Na+ as affected by Cr, Ni and Pb was similar but more pronounced for K+ than Na+. The inhibition of physiological variables depicted the following trend: Na+ loss 〉 K+ loss 〉 glutamine synthetase 〉 NH4 uptake 〉 growth 〉 N03 − uptake 〉 nitrate reductase 〉 heterocyst frequency. This study therefore suggests that loss of electrolytes can be used as a first signal of metal toxicity in cyanobacteria. However, further study is needed to confirm whether the abnormality induced by nickel (branch formation) is a physiological or genetic phenomenon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01141365
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  • 2
    Electronic Resource
    Electronic Resource
    Grain size and geochemical partitioning of heavy metals in sediments of the Damodar River – a tributary of the lower Ganga, India (1999)
    Springer
    Environmental geology 39 (1999), S. 90-98 
    Details
    ISSN: 1432-0495
    Keywords: Key words Damodar River ; Heavy metals ; Grain size ; Chemical fractionation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  The distribution of Si, Al, Fe, Mn, Cu, Zn, Ni and Cr in different grain-size fractions and geochemical association of Fe, Mn, Cu and Zn with 〈63-μm size fraction of bed sediments of Damodar River has been studied. In general, concentrations of heavy metals tend to increase as the size fractions get finer. However at two sites, near mining areas, the coarser particles show similar or even higher heavy metal concentrations than finer ones. The higher residence time and/or presence of coarser particles from mining wastes are possibly responsible for higher metal content in the coarser size fractions. The chemical fractionation study shows that lithogenic is the major chemical phase for heavy metals. Fe and Mn are the major elements of the lithogenic lattice, constituting 34–63% and 22–59%, respectively, of total concentrations. Fe-Mn oxide and organic bound fractions are significant phases in the non-lithogenic fraction. The carbonate fraction is less significant for heavy metal scavenging in the present environment and shows the following order of abundance Zn〉Cu〉Mn〉Fe. The exchangeable fraction of the Damodar sediments contains very low amounts of heavy metals suggesting poor bioavailability of metals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002540050439
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  • 3
    Electronic Resource
    Electronic Resource
    Utilization of wild relatives in the genetic improvement of Arachis hypogaea L. (1986)
    Springer
    Theoretical and applied genetics 72 (1986), S. 164-169 
    Details
    ISSN: 1432-2242
    Keywords: Arachis ; Autotetraploid ; Chromosome pairing ; Genomic relationships ; Recombinations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Autotetraploids were established from 8 diploid wild species of section Arachis. In all the autotetraploids the chromosomes paired largely as bivalents even though they possess the ability to pair as multivalents. Pollen and pod fertility in the C1 generation were not directly associated with chromosome pairing. The C2 generation autotetraploids showed a gradual increase in bivalent associations and pollen and pod fertility. The identification of two genomes, A and B, in the diploid species and in the tetraploid, A. hypogaea, of the section Arachis, a fairly good crossability, and the type of chromosome associations observed in hybrids between A. hypogaea and the autotetraploids of wild Arachis species indicated good prospects of utilizing autotetraploids as genetic bridges in transferring desired traits from these taxa into groundnut.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00266988
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  • 4
    Electronic Resource
    Electronic Resource
    Utilization of wild relatives in the genetic improvement of Arachis hypogaea L. (1986)
    Springer
    Theoretical and applied genetics 72 (1986), S. 433-439 
    Details
    ISSN: 1432-2242
    Keywords: Arachis ; Amphidiploids ; Genomes ; Chromosome pairing ; Recombinations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Synthetic amphidiploids were established in 32 combinations involving 8 diploid wild species representing both A and B genomes of section Arachis. Bivalent and multivalent associations in the amphidiploids of 7 A genome species confirm that these species have identical genomes. Contrastingly, high bivalent frequencies in amphidiploids involving the A and B genome species suggest that A. batizocoi has a distinct ‘B’ genome that is partially homologous to the other genome ‘A’ represented in the rest of the species. Crossability, chromosome pairing and pollen and pod fertility in hybrids between A. hypogaea and amphidiploids have revealed that these amphidiploids can be used as a genetic bridge for the transfer of genes from the wild species into the cultivated groundnut.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00289523
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  • 5
    Electronic Resource
    Electronic Resource
    Optical differentiation of orthorhombic superconductors such as YBa2Cu3O7 from their tetragonal precursor material (1988)
    Springer
    Journal of superconductivity 1 (1988), S. 35-44 
    Details
    ISSN: 1572-9605
    Keywords: ErBa2Cu3O7 ; superconductivity ; optical microscopy ; phase differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The orthorhombic superconducting phase of YBa2Cu3O7 is shown to be differentiable from its tetragonal precursor by optical microscopy. Individual grains 1 μm in diameter or larger are found to either exhibit the color of the compensator in reflected polarized light (tetragonal material) or to change colors from the compensator (orthorhombic material). By using color differences, retained tetragonal material and the orthorhombic nature of untwinned areas of grains are identified. The advantage to producing better superconducting single crystals and sintered polycrystalline materials is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00617949
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  • 6
    Electronic Resource
    Electronic Resource
    Novel technique for crystal growth of superconducting ErBa2Cu3O7 (1988)
    Springer
    Journal of superconductivity 1 (1988), S. 181-190 
    Details
    ISSN: 1572-9605
    Keywords: ErBa2Cu3O7 ; crystal growth ; microscopy ; superconductivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract Millimeter-sized crystals of ErBa2Cu3O7 were fortuitously grown while sintering a flat disk. It was possible to separate individual crystals from the sintered mass and measure their properties. The resistive transition and onset of magnetic transition of a single crystal was 93 K and the resistive transition width was 〈 1 K. Flux expulsion was observed and individual crystals could be levitated by a magnetic field. Crystals showed unusual growth features. They were heavily corrugated along the part of the crystal that grew parallel to the top surface of the disk and that coincided with thec axis of the unit cell. Crystals were characterized by X-rays, electron microscopy, and optical microscopy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00617662
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of low-temperature rearing on heat shock protein synthesis and heat sensitivity in Drosophila melanogaster (1988)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 9 (1988), S. 193-201 
    Details
    ISSN: 0192-253X
    Keywords: thermotolerance ; hsp 23 ; heat shock genes ; hsr 93D ; cold rearing ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The patterns of synthesis of heat shock proteins (hsp) and heat sensitivity to elevated temperatures in larvae of Drosophila melanogaster reared since hatching at 20°C (warmreared) or at 10°C (cold-reared) were compared. The pattern of hsp synthesis in salivary glands from the cold- and warm-reared late-third-instar larvae exposed for l hr to 33°C or to 37°C was generally similar except for remarkable differences in the 23 kd hsp and a heat-inducible 14 kd polypeptide. The hsp 23 was abundantly synthesised in control as well as heat-shocked warm-reared larval salivary glands, its synthesis in heat-shocked glands being dependent on new transcription. The synthesis of hsp 23 was much less in control glands of cold-reared larvae and was not further inducible by heat shock. The 14 kd polypeptide synthesis was greater in control as well as heat-shocked salivary glands of cold-reared larvae, whereas, in the warm-reared ones, its activity was much less. The cold-reared larvae showed greater sensitivity to elevated temperature; fewer adults eclosed when the cold-reared late-third-instar larvae were exposed to 40°C for l hr and also a pretreatment at 37°C for l hr was less effective in stopping the killing effect of a subsequent 40°C heat shock in cold-reared than in warmA-reared larvae. The greater thermosensitivity of the cold-reared larvae may be correlated with the altered patterns of heat shock gene transcription and translation in cold-reared larvae.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020090305
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  • 8
    Electronic Resource
    Electronic Resource
    Artifacts introduced by ion milling in Al-Li-Cu alloys (1988)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 355-361 
    Details
    ISSN: 0741-0581
    Keywords: Electropolishing ; TEM ; δ′ ; T1 and θ′ precipitates ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Ion milling is commonly used to prepare specimens for observation under transmission electron microscope (TEM). This technique sometimes introduces artifacts in specimens contributing to misleading interpretation of TEM results as observed in the present investigation of Al-Li-Cu alloys. This type of alloy, in general, contains several kinds of precipitates, namely δ′ T1, and θ′. It is found that ion milling even for a short time produces drastic changes in the precipitate characterics as compared to standard electropolishing methods of specimen preparation for TEM. Careful analysis of selected area diffraction patterns and micrographs shows that after ion milling δ′ precipitates are very irregular, whereas other precipitates coarsen and they are surrounded by misfit dislocations. In situ hot-stage TEM experiments were performed to relate the microstructure to that observed in the ion-milled specimen. Results and causes of ion milling effects on the microstructure are discussed in relation to standard electropolishing techniques and in situ hot-stage experiment.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1060080404
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