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
  • Electronic Resource  (3)
  • 2005-2009
  • 2000-2004  (1)
  • 1985-1989  (2)
  • 1960-1964
  • fraction of adhered segments  (2)
  • Key words: Ultrasound densitometry — Body composition — Fat mass — Lean body mass — Epidemiology.  (1)
Material
  • Electronic Resource  (3)
Years
  • 2005-2009
  • 2000-2004  (1)
  • 1985-1989  (2)
  • 1960-1964
Year
Keywords
  • 1
    ISSN: 1435-1536
    Keywords: Polymer adsorption ; IR spectrometry ; fraction of adhered segments ; silica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The adsorption of N-ethylpyrrolidone (NEP), oligomeric and polymeric vinylpyrrolidone (OVP, PVP) on silica (Aerosil 200) from CHCl3 solution is investigated by IR spectrometry. The influence of the annealing temperature of the silica on the adsorbed amount and on the fraction of adhered segments was studied. The dependences of the amount adsorbed on solution concentration result for NEP in a Langmuir isotherm for OVP and PVP in high affinity isotherms. The fraction of adhered H-bridged carbonyl groups determined by compensation procedures, the fraction of surface SiOH groups occupied and the multiple interaction quotientQ show different dependences on the amount adsorbed for the measured adsorptives, indicating different interactions of the monomeric segments with the surface groups. This behaviour is explained by comparing the amount adsorbed in saturation with monolayer capacities, surface concentration of SiOH groups and frequency shifts. A splitting of the band of the bound carbonyl groups in a double peak was observed with OVP and PVP, referring to an additional interaction of polymer segments neighboured to specifically bound segments.
    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
    Colloid & polymer science 263 (1985), S. 381-387 
    ISSN: 1435-1536
    Keywords: polymer adsorption ; microcalorimetry ; enthalpy of adsorption ; fraction of adhered segments ; silica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Adsorption enthalpies of N-ethylpyrrolidone, oligomeric and polymeric vinylpyrrolidone from CHCl3 solution on silica interfaces (Aerosil 200) have been measured at 25 °C by microcalorimetry. The dependence on surface coverage has been examined using measured adsorption isotherms. Binding enthalpies are calculated with fractions of adhered segments obtained by IR spectrometry and wetting enthalpies received from calorimetry. Fractions of adhered segments are derived from the adsorption enthalpies assuming equal binding enthalpies of monomers and polymer segments and considering desorption enthalpies of the solvent depending on the surface area of the polymer segments. The resulting enthalpies are compared with literature values from other solvents and the incongruity of the fraction of adhered segments obtained by IR, ESR, NMR and microcalorimetry is explained.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-0827
    Keywords: Key words: Ultrasound densitometry — Body composition — Fat mass — Lean body mass — Epidemiology.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Body mass is known to be related to measures of bone mineral density (BMD) as well as to parameters of quantitative ultrasound (US). To examine the effect of the body compartment's fat mass and lean body mass on quantitative ultrasonic bone parameters, data from a sample of 3241 German women were analyzed. Anthropometric measures, including skinfold thickness, were obtained from standardized measurements, and fat and lean body mass were derived from classical regression formulas based on skinfold measurements. Ultrasonic bone measurements were performed on the right os calcis, and speed of sound (SOS) and broadband ultrasound attenuation (BUA) were determined. Women were grouped into pre- and postmenopausal status; postmenopausal women were further stratified into ever and never hormone-replacement user. Correlation analysis indicated lean body mass to be stronger correlated with BUA than fat mass in both pre- (r = 0.23; P= 0.0001) and postmenopausal women with (r = 0.19; P= 0.0001) and without hormone replacement therapy (HRT) (r = 0.26; p = 0.0001). SOS demonstrated very small or no associations with body mass or its components. Multiple linear regression models were used to describe the relationship among body weight, fat mass, and lean body mass on BUA after adjustment for confounding variables. Both in pre- and postmenopausal women lean body mass was more strongly related to BUA than fat mass. However, body mass measures explained only small amounts of the overall variance in BUA (R2= 1–3% in premenopausal women; R2= 1% postmenopausal with HRT; R2= 4–5% in postmenopausal women without HRT). In conclusion, the strong influence of body mass and its components previously reported for BMD was not observed for quantitative ultrasonic bone parameters.
    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...