ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • Analytical Chemistry and Spectroscopy  (2)
  • phase separation
  • 1990-1994  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of sol gel science and technology 1 (1993), S. 35-46 
    ISSN: 1573-4846
    Keywords: Flory-Huggins' theory ; phase separation ; spinodal decomposition ; sol-gel method ; porous silica gel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Silica gels with well-defined pores both in micrometer and nanometer ranges were obtained by acid-catalyzed hydrolysis and polymerization of tetramethoxysilane in the presence of formamide. The micrometer-range structures of these gels are studied in terms of the phase diagram of the quasi two-component system, namely solvent-rich and silica-rich end compositions. The resulting interconnected structures and aggregates of particles are related to the occurrence of spinodal phase separation. The composition region that gave interconnected structures for the present system was much more limited and their characteristic sizes were much smaller than those for the previously reported systems containing an organic polymer. These results could be explained qualitatively by the effect of the degree of polymerization on the Flory-Huggins' type free energy change of mixing.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1573-4846
    Keywords: porous silica gel ; light scattering ; phase separation ; spinodal decomposition ; Cahn's theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The investigation of phase separation processes induced by polymerization reactions of tetramethoxysilane (TMOS) was attempted by a time-resolved light scattering method for TMOS-formamide-water system under the acid-catalyzed condition. Since the early stage of the phase separation exhibits very fast kinetics and weak scattering intensity, the experimental set-up was designed so as to reduce the experimental error and to obtain higher time resolution by using a laser beam expander. For the gels whose morphologies are ‘interconnected structure’ and ‘aggregates of particles,’ it was experimentally found that the wavelength of the concentration fluctuation in the early stage of phase separation was time-independent and its amplitude grew exponentially with time. This suggests that these samples phase-separate by spinodal decomposition mechanism. In the later stages of phase separation, the coarsening process and the following structure-freezing process by gel-network formation were observed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Serum transferrin precipitated with anti-transferrin serum was unalysed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS). The transferrin-antibody complex in the immuno-precipitates was separated into transferrin and IgG in an acidic pH, which is the usual condition of loading on MALDI-TOFMS. Ions of IgG and other minor components were not superimposed on the transferrin ions. Transferrin isoforms with different carbohydrate contents could be identified by this simple method easier than by affinity chromatography requiring the time-consuming preparation of an insolubilized specific antibody. The transferrin isoform with a molecular weight of ∼ 2.2 kDa smaller than normal transferrin, which is contained in the serum from patients with carbohydrate-deficient glycoprotein (CDG) syndrome, was identified by this method. In addition to the M1+ ion detected using sinapinic acid as a matrix, the M2+ and M3+ ions of transferrin were clearly detected using α-cyano-4-hydroxycinnamic acid as matrix and the molecular weight heterogeneity was identified more clearly in multivalent ions than that in the M1+ ion. The MALDI-TOF analysis of immunoprecipitates may serve as a simple and sensitive method to identify the molecular weight heterogeneity of various biological materials.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 28 (1993), S. 1395-1402 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tandem mass spectrometry (MS/MS) is an attractive technique for sequencing membrane proteins because it can be applied to peptides in mixtures that are difficult to separate chromatographically. To evaluate the suitability of MS/MS sequencing for membrane proteins and to develop protocols for the preparation of the cleaved peptides, we employed the well characterized apoproteins of bacteriorhodopsin and bovine rhodopsin, i.e. bacterioopsin and opsin, respectively. Without separation, nine out of ten peptides resulting from cyanogen bromide cleavage of bacterioopsin were detected by fast atom bombardment MS, the single undetected fragment being a tetrapeptide that was presumably hidden in the low-m/z matrix background. Furthermore, MS/MS was used to confirm the sequence of all the peptides detected with m/z values below 3.5 kDa (40% of the protein). Bovine opsin was analyzed in a similar fashion. Tandem MS/MS has thus allowed the sequencing of substantial portions of two integral membrane proteins by the analysis of unseparated peptide mixtures, demonstrating for the first time that this technique can obviate some of the most serious difficulties associated with sequencing membrane proteins, namely the difficult-to-achieve separation of the ‘sticky’ peptide fragments.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...