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  • Articles: DFG German National Licenses  (8)
  • Electronic Resource  (8)
  • 2005-2009
  • 1995-1999  (8)
  • 1985-1989
  • 1996  (8)
Source
  • Articles: DFG German National Licenses  (8)
Material
  • Electronic Resource  (8)
Years
  • 2005-2009
  • 1995-1999  (8)
  • 1985-1989
Year
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical journal international 127 (1996), S. 0 
    ISSN: 1365-246X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: A record of normal-reversed-polarity transition has been obtained from a 4 m thickness of loess exposed at a section near Lanzhou, China. Magnetostratigraphic studies suggest it may represent a reversal bounding the onset of a reversed-polarity zone within the Jaramillo Normal Subchron. The natural remanent magnetization consists of two components: a low-coercivity (≤20mT), low-unblocking-temperature (≤300°C) component of viscous origin and a high-coercivity (〉20mT), high-unblocking-temperature (250–700 °C) component carrying the characteristic remanence. Mineral magnetic analyses confirmed the presence of magnetite, its low-temperature oxidation products and haematite, each contributing to the remanence properties. Grain size and concentration showed limited variations and there was little evidence for the presence of the ultrafine magnetic phase commonly associated with palaeosol formation. Pedogenic processes appeared negligible and their effects unimportant, with detrital processes dominating the mineralogy and most probably the acquisition of the characteristic remanence. The reversal record was characterized by the decay and recovery of the geocentric axial dipole term with large directional swings occurring during periods of reduced relative palaeofield intensity. The virtual geomagnetic poles traced a complex path exhibiting no particular geographical confinement. Relative palaeofield intensity determinations were insensitive to the choice of normalization parameter and showed a distinctive asymmetry. Striking similarities were observed with the Matuyama-Jaramillo reversal record, obtained from the same section (Rolph 1993), and the Steens Mountain reversal record (Prévot el al. 1985), lending further support for the existence of unusually high post-transitional field intensities
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical journal international 124 (1996), S. 0 
    ISSN: 1365-246X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Accurate determination of the strength of the ancient geomagnetic field is limited by mineralogical alteration that may occur when samples are heated to produce a thermoremanent magnetization (Thellier & Thellier 1959; Shaw 1974). By using direct microwave excitation of the magnetic grains we have been able to form a thermoremanent magnetization without significantly heating the bulk sample, thus avoiding thermal alteration (Walton et al. 1993). Incorporation of this new microwave heating technique with the conventional Thellier palaeointensity method has dramatically reduced the scatter of archaeointensity results from Peruvian ceramics and clearly defined how the field strength has varied in Peru over the past 2000 years. The new microwave technique will therefore enhance the feasibility of archaeointensity dating and provide accurate field strength data for geomagnetic modelling.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 52 (1996), S. 2883-2885 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Surveys in geophysics 17 (1996), S. 161-167 
    ISSN: 1573-0956
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of Indian philosophy 24 (1996), S. 231-264 
    ISSN: 1573-0395
    Source: Springer Online Journal Archives 1860-2000
    Topics: Philosophy
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1617-4623
    Keywords: Key words Saccharomyces cerevisiae ; Chitin synthases ; Septum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Predicted protein sequences of fungal chitin synthases can be divided into a non-homologous N-terminal region and a C-terminal region that shows significant homology among the various synthases. We have explored the function of these domains by constructing a series of nested deletions, extending from either end, in the CHS1 and CHS2 genes of Saccharomyces cerevisiae. In both cases, most or all of the sequences encoding the non-homologous N-terminal region (one-third of the protein for Chs1p and about one-fourth for Chs2p) could be excised, with little effect on the enzymatic activity in vitro of the corresponding synthase or on its function in vivo. However, further small deletions (20–25 amino acids) into the homologous region were deleterious to enzymatic activity and function, and often led to changes in the zymogenic character of the enzymes. Similarly, relatively small (about 75 amino acids) deletions from the C-terminus resulted in loss of enzymatic activity and function of both synthases. Thus, it appears that all the information necessary for membrane localization, enzymatic activity and function resides in the homologous regions of Chs1p and Chs2p, a situation that may also apply to other chitin synthases.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-904X
    Keywords: anticancer agents ; poorly water soluble agents ; nanoparticles ; etoposide ; camptothecin ; piposulfan and paclitaxel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. Determine if wet milling technology could be used to formulate water insoluble antitumor agents as stabilized nanocrystalline drug suspensions that retain biological effectiveness following intravenous injection. Methods. The versatility of the approach is demonstrated by evaluation of four poorly water soluble chemotherapeutic agents that exhibit diverse chemistries and mechanisms of action. The compounds selected were: piposulfan (alkylating agent), etoposide (topoisomerase II inhibitor), camptothecin (topoisomerase I inhibitor) and paclitaxel (antimitotic agent). The agents were wet milled as a 2% w/v solids suspension containing 1 % w/v surfactant stabilizer using a low energy ball mill. The size , physical stability and efficacy of the nanocrystalline suspensions were evaluated. Results. The data show the feasibility of formulating poorly water soluble anticancer agents as physically stable aqueous nanocrystalline suspensions. The suspensions are physically stable and efficacious following intravenous injection. Conclusions. Wet milling technology is a feasible approach for formulating poorly water soluble chemotherapeutic agents that may offer a number of advantages over a more classical approach.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; Chitin synthases ; Septum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Predicted protein sequences of fungal chitin synthases can be divided into a non-homologous N-terminal region and a C-terminal region that shows significant homology among the various synthases. We have explored the function of these domains by constructing a series of nested deletions, extending from either end, in theCHS1 andCHS2 genes ofSaccharomyces cerevisiae. In both cases, most or all of the sequences encoding the non-homologous N-terminal region (one-third of the protein for Chs1p and about one-fourth for Chs2p) could be excised, with little effect on the enzymatic activity in vitro of the corresponding synthase or on its function in vivo. However, further small deletions (20–25 amino acids) into the homologous region were deleterious to enzymatic activity and function, and often led to changes in the zymogenic character of the enzymes. Similarly, relatively small (about 75 amino acids) deletions from the C-terminus resulted in loss of enzymatic activity and function of both synthases. Thus, it appears that all the information necessary for membrane localization, enzymatic activity and function resides in the homologous regions of Chs1p and Chs2p, a situation that may also apply to other chitin synthases.
    Type of Medium: Electronic Resource
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