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  • photometric detector  (2)
  • Protein homology detect  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 36 (1993), S. 67-78 
    ISSN: 1432-1432
    Keywords: Structure-based scoring matrix MDPRE ; Phyletic relationship of protein structure ; Spatial preference factor ; Sequence alignment ; Protein homology detect ; Globins ; Immunoglobulins ; Cytochromes c ; Serine proteinases ; Dinucleotide-binding domains
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A structure-based scoring matrix MDPRE was derived from amino acid spatial preferences in protein structures. Sequence alignment and evolutionary studies by using MDPRE matrix gave similar results as those from ordinary sequence and structure alignments. It is interesting that a matrix derived from structure data solely could give comparable alignment results, strongly indicating the intimate connection between protein sequences and structures. The branch order and length from this approach were close to those obtained by a structure comparison method. Thus, by applying this structure-based matrix, the trees obtained should reflect evolutionary characteristics of protein structure. This approach takes advantage over a direct structure comparison in that (1) only a sequence and MDPRE matrix are needed, making it simple and widely applicable (especially in the absence of 3-dimensional protein structure data); (2) an established algorithm for sequence alignment and tree building could be employed, providing opportunities for direct comparison between matrices from different methodologies. One of the most striking features of this method is its capability to detect protein structure homologies when the sequence identities are low. This was well reflected in the given examples of the alignment of dinucleotidebinding domains.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Microchimica acta 92 (1987), S. 21-28 
    ISSN: 1436-5073
    Keywords: anthraquinone ; luminescence ; photometric detector ; gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Anthraquinone can be determined, following gas chromatographic separation, by photometry of its luminescence in excited nitrogen. The spectrum consists of some broad bands, the most prominent of which peak at 460–480 nm. The minimum detectable amount (S/N=2), using a packed column, is surprisingly low at ca. 0.5 pg or 0.24 fmol/s (2.4×10−16mol/s); the linear range spans three to four orders of magnitude; and the detector is capable of operating under temperature-programmed GC conditions. While anthraquinone is the strongest responding analyte of its kind, similar though somewhat weaker responses are produced by certain types of aroyl compounds. All other tested groups of organics give only extremely weak, negative responses (decreases in background luminescence) at some 105 to 106 higher concentrations. Quenching of anthraquinone luminescence can occur: As a typical example, a 50% reduction in response is produced by a ca. 100 ppmv/v level of co-elutingn-butane in the nitrogen carrier (a more than millionfold weight excess for a 1 pg peak of anthraquinone).
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Microchimica acta 92 (1987), S. 29-35 
    ISSN: 1436-5073
    Keywords: beta radiation ; luminescence ; photometric detector
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract It was recently found that typical Chromatographic carrier gases such as argon or nitrogen could be used in a modified flame photometric detector for general or selective determination of eluted molecules. The detector was powered not by a flame but by a radioactively stimulated, mild discharge. The luminescence arose from the second positive system of nitrogen (in argon), and various emissions from aroyl-containing molecules (in nitrogen). This study describes experiments that take away not only the flame but also the discharge: The energy that produces the luminescence is derived solely from the beta decay of63Ni. Because of this low power input, the sensitivity of the present beta-driven photometric detector (β-PD) is limited to about 25 ppm of nitrogen (in argon), and to about 5 pg/s for benzaldehyde and other well-responding aroyl compounds (in nitrogen). In accordance with mechanisms postulated earlier, other types of molecules do not produce significant responses in the absence of an electrical field.
    Type of Medium: Electronic Resource
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