Library

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
  • 1985-1989  (5)
  • 1955-1959  (1)
  • Polymer and Materials Science  (4)
  • SOS response  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 215 (1989), S. 483-489 
    ISSN: 1617-4623
    Keywords: SOS response ; ColE1 plasmid ; Catabolite repression ; Gene fusion ; RecA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Three mutations were introduced into the cea promoter using oligonucleotide directed mutagenesis. The resulting mutant promoter has the Escherichia coli consensus sequences at its-35 and-10 positions, separated by the optimal spacing. In addition, a plasmid with a mutation in one of the two LexA repressor binding sites in the cea regulatory region was isolated that decreases homology with the consensus LexA binding site. The effects of these mutations on cea expression were studied in cea-lacZ protein fusions. The promoter-up mutant, when present in a multicopy plasmid, showed a shorter induction lag when compared to the wild-type cea gene, and there was less of an effect of the catabolite repression system on cea expression. However, when present in a single copy in the bacterial chromosome, catabolite repression and an induction delay were observed, despite the increased strength of the promoter. The operator mutant showed a slightly higher basal level of expression, but was still repressible. Induction occurred with a shortened lag period, but the effects were not as great as with the promoter mutant. These results support the idea that tight repression by LexA contributes to the delay in cea induction.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 215 (1989), S. 537-542 
    ISSN: 1617-4623
    Keywords: Catabolite repression ; SOS response ; Colicin E1 ; LexA protein ; Cyclic AMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Analysis of the induction of expression of cea-lacZ fusions in cya and crp mutants showed that catabolite repression affects the kinetics of induction and the rate of induced synthesis. In a cya mutant, addition of cAMP reduced the induction lag and increased the amount of β-galactosidase produced. The CRP-cAMP complex was found to bind to two sites 5′ to the cea promoter, but deletion analysis showed that only one of these was involved in the control of cea. Deletion of this site resulted in a loss of the stimulatory effects of cAMP in a cya mutant.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 2415-2424 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aminophenoxycyclotriphosphazenes have been used as curing agents for epoxy resins. The thermal curing was performed in stages at 120-125 and 175-180°C followed by postcuring at 225°C to give tough brown polymers. The thermal curing reaction was monitored using FTIR and differential scanning calorimetry. Thermogravimetric analysis of the cured resins has shown thermal stability up to 350-340°C. The char yield obtained in nitrogen at 800°C was about 55-42% and in air at 700°C was about 40-32%. Graphite cloth laminates were prepared. The mechanical properties evaluated were found superior to those of commonly used epoxy resin systems. These resins are useful for making fire- and heat-resistant composites, laminates, molded parts, and adhesives.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 0935-9648
    Keywords: Interfacial Structure ; Wettability ; Long-Chain Thiols ; on Gold ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The interfacial properties of organic materials are of critical importance in many applications, especially the control of wettability, adhesion, tribology, and corrosion. The relationships between the microscopic structure of an organic surface and its macroscopic physical properties are, however, only poorly understood. This short review presents a model system that has the ease of preparation and the structural definition required to provide a firm understanding of interfacial phenomena. Long-chain thiols, HS(CH2)nX, adsorb from solution onto gold and form densely packed, oriented monolayers. By varying the terminal functional group, X, of the thiol, organic surfaces can be created having a wide range of structures and properties. More, complex systems can be constructed by coadsorbing two or more thiols with different terminal functional groups or with different chain lengths onto a common gold substrate. By these techniques, controlled degrees of disorder can be introduced into model surfaces. We have used these systems to explore the relationships between the microscopic structure of the monolayers on a molecular and supramolecular scale and their macroscopic properties. Wettability is a macroscopic interfacial property that has proven of particular interest.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 16 (1955), S. 31-44 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The polymerization of vinyl acetate has been studied at temperatures down to -40°C. by means of a specially designed apparatus. The object of the experiments is to preparer polyvinyl acetates of as linear a character as possible by working at low temperatures in order to avoid transfer reaction to accumulating polymer. Polymers prepared at a number of temperatures have been examined osmotically and by the light-scattering technique. Using the latter technique, it has been shown quite clearly that the size of the molecule, as measured by the dissymmetry measurements, gets smaller and smaller for a given molecular weight as the temperature of synthesis is decreased. It is believed that if the synthesis is carried out at temperatures below -30°C., then the molecules formed are predominantly linear in character.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Rapid Communications 6 (1985), S. 57-63 
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...