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  • 1
    Electronic Resource
    Electronic Resource
    Sulcus temperature distributions in the absence and presence of oral hygiene (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 27 (1992), S. 0 
    Details
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In this study we investigated the possibility of using sulcus temperature measurements as an early indicator for the beginning of gingival inflammation. Sulcus temperature distributions over the arches appeared to obey a quadratic polynomial. With a test group of 10 volunteers, all dental students, small changes in temperature were measured after subjects refrained from all oral hygiene: A slight but significant tendency for the frontal temperature to increase after 14 days of no oral hygiene was, however, present. The quality of a quadratic polynomial fit of the temperature distributions over the arches decreased significantly, already after 3 d of non-oral hygiene. This indicates that the coefficient of quadratic correlation for the temperature distributions over the arches is a measure for the oral hygiene of patients and for changes in the physiology of gingival tissues. Furthermore, as its decrease was concurrent with an increase in plaque and gingival indices, it might serve as an early indicator for the beginning of gingival inflammation. However, further development work is needed in order to make this approach useful as a clinical tool.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0765.1992.tb01810.x
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  • 2
    Electronic Resource
    Electronic Resource
    The influence of surface free energy and surface roughness on early plaque formation (1990)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of clinical periodontology 17 (1990), S. 0 
    Details
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract Previous in vivo studies suggested that a high substratum surface free energy (s.f.e.) and an increased surface roughness facilitate the supragingival plaque accumulation. It is the aim of this clinical trial to explore the “relative” effect of a combination of these surface characteristics on plaque growth. 2 strips, one made of fluorethylenepropylene (FEP) and the other made of cellulose acetate (CA) (polymers with surface free energies of 20 and 58 erg/cm2, respectively) were stuck to the labial surface of the central incisors of 16 volunteers. Half the surface of each strip was smooth (Ra ± 0.1 μm) and the other half was rough (Ra ± 2.2 μm). The undisturbed plaque formation on these strips was followed over a period of 6 days. The plaque extension at day 3 and 6 was scored planimetrically from color slides. Finally, of 6 subjects samples were taken from the strips as well as from a neighbouring smooth tooth surface (s.f.e. 88 erg/cm2; Ra ± 0.14 μm). These samples were analysed with a light microscope to score the proportion of coccoid cells, and small, medium, and large rods or fusiform bacteria. At day 3, a significant difference in plaque accumulation was only obtained when a rough surface was compared with a smooth surface. However, at day 6, significantly less plaque was recorded on FEP smooth (19.4%) when compared with CA smooth (39.5%). Between FEP rough (96.8%) and CA rough (98.2%), no significant difference appeared. The latter were of course significantly higher than the scores of the smooth surfaces. Small differences in bacterial composition appeared: the highest % of coccoid cells was observed on FEP smooth (86.2%) and the lowest % on FEP rough (78.5%) and CA rough (82.8%). The results of this study suggested that the influence of the surface roughness on plaque accumulation and plaque composition is more prominent than the influence of the surface free energy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-051X.1990.tb01077.x
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  • 3
    Electronic Resource
    Electronic Resource
    Assessment of bacterial biosurfactant production through axisymmetric drop shape analysis by profile (1991)
    Springer
    Applied microbiology and biotechnology 35 (1991), S. 766-770 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Axisymmetric drop shape analysis by profile (ADSA-P) is a technique developed in colloid and surface science to simultaneously determine the contact angle and liquid surface tension from the profile of a droplet resting on a solid surface. In this paper is described how ADSA-P can be employed to assess bacterial biosurfactant production. Nine Streptococcus mitis strains, two of which are known to produce biosurfactants, and two S. salivarius strains, which do not produce biosurfactants, were suspended at two concentrations in a 10-mm potassium phosphate buffer, pH 7.0. Subsequently, a 100-μl droplet of each suspension was put on a fluoroethylenepropylene surface and the profile of the droplet determined with a contour monitor as a function of time up to 2 h. The surface tension of these suspensions was then calculated from the droplet profiles with ADSA-P. The surface tension of suspensions of the two non-producing strains remained stable within 4 mJ·m−2, whereas the surface tension of suspensions of five out of the nine S. mitis strains employed, including those of the known producer strains, decreased significantly (up to 26 mJ·m−2). This decrease was, in addition, concentration dependent. From these observations, we decided that all strains for which these concentration-dependent decreases were observed, could be regarded as biosurfactant producers. In order to rule out the possibility that the surface tension decreases observed were due to the collection of cells at the suspension-air interface, we investigated whether there was a relationship between surface tension decrease and hydrophobicity of the cells, as assessed by contact angle measurements and bacterial adhesion to hydrocarbons. Since no such a relationship was found, it can be concluded that ADSA-P is an excellent technique, based on using small amounts of cells to rapidly determine whether or not a bacterial strain produces biosurfactants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00169892
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  • 4
    Electronic Resource
    Electronic Resource
    Biosurfactant production by thermophilic dairy streptococci (1994)
    Springer
    Applied microbiology and biotechnology 41 (1994), S. 4-7 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract. Biosurfactant production of eight Streptococcus thermophilus strains, isolated from heat exchanger plates in the downstream side of the regenerator section of pasteurizers in the dairy industry has been measured using axisymmetric drop shape analysis by profile (ADSA-P). Strains were grown in M17 broth with either lactose, saccharose or glucose added. After harvesting, cells were suspended in water or in 10 mm potassium phosphate buffer, pH 7.0, and suspension droplets were put on a piece of FEP-Teflon. Changes in droplet profile were analysed by ADSA-P to yield the surface tension decrease due to biosurfactant production as a function of time. Surface tension decreases larger than 8 mJ·m−2 were taken as indicative of biosurfactant production. Only five strains produced biosurfactants in water, solely when saccharose was added to the growth medium. In buffer, all strains produced biosurfactants and production was generally greater than in water. Also, most strains suspended in buffer produced maximally when saccharose was added to the growth medium, whereas one strain produced maximally in buffer upon the addition of glucose. Four strains suspended in buffer produced biosurfactants when glucose was added and only two strains when lactose was added. The possible role of these biosurfactants as anti-adhesives in the dairy industry and for the survival of these strains in natural systems is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00166073
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  • 5
    Electronic Resource
    Electronic Resource
    Biosurfactant production by thermophilic dairy streptococci (1994)
    Springer
    Applied microbiology and biotechnology 41 (1994), S. 4-7 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Biosurfactant production of eight Streptococcus thermophilus strains, isolated from heat exchanger plates in the downstream side of the regenerator section of pasteurizers in the dairy industry has been measured using axisymmetric drop shape analysis by profile (ADSA-P). Strains were grown in M17 broth with either lactose, saccharose or glucose added. After harvesting, cells were suspended in water or in 10 mm potassium phosphate buffer, pH 7.0, and suspension droplets were put on a piece of FEP-Teflon. Changes in droplet profile were analysed by ADSA-P to yield the surface tension decrease due to biosurfactant production as a function of time. Surface tension decreases larger than 8 mJ·m−2 were taken as indicative of biosurfactant production. Only five strains produced biosurfactants in water, solely when saccharose was added to the growth medium. In buffer, all strains produced biosurfactants and production was generally greater than in water. Also, most strains suspended in buffer produced maximally when saccharose was added to the growth medium, whereas one strain produced maximally in buffer upon the addition of glucose. Four strains suspended in buffer produced biosurfactants when glucose was added and only two strains when lactose was added. The possible role of these biosurfactants as anti-adhesives in the dairy industry and for the survival of these strains in natural systems is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00166073
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  • 6
    Electronic Resource
    Electronic Resource
    Adsorption and desorption of colloidal particles on glass in a parallel plate flow chamber—Influence of ionic strength and shear rate (1994)
    Springer
    Colloid & polymer science 272 (1994), S. 478-486 
    Details
    ISSN: 1435-1536
    Keywords: Parallel plate flow chamber ; adsorption ; desorption ; blocked area ; image analysis
    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 and desorption rates of 736 nm diameter polystyrene particles on glass were studiedin situ using a parallel plate flow chamber and automated image analysis. Adsorption and desorption rates were measured simultaneously during deposition, enabling the determination of initial deposition rates, blocked areas per particle, desorption rate coefficients, and the number of adhering particles in the stationary state. Deposition experiments were done from suspensions with different potassium nitrate concentrations (1, 10 and 50 mM) and at varying shear rates (15 to 200 s−1). The initial deposition rate, the desorption rate, the blocked area per particle and the number of adhering particles in the stationary state showed major variations with the shear rate and the ionic strength of the suspension. At low ionic strength, the number of adhering particles showed an oscillatory behavior in time, presumably due to a varying interaction between particle and collector surface. Blocked areas, determined from deposition kinetics, ranged 705 to 2374 cross-sections at low ionic strength, and from 10 to 564 at high ionic strength and corresponded well with those estimated from local pair distribution functions which were obtained from an analysis of the spatial arrangement of the adhering particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00659461
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  • 7
    Electronic Resource
    Electronic Resource
    Mikrobielle Werkstoffzerstörung - Schadensfälle und Gegenmaßnahmen für Kunst- und Naturstoffe. Mikrobiologische Zerstörung von Silikon-Elastomeren (1994)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 45 (1994), S. 170-171 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Microbial deterioration of materials - case histories and countermeasures for plastics and natural materials: Biodeterioration of silicone elastomers
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19940450307
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  • 8
    Electronic Resource
    Electronic Resource
    Amount and surface structure of albumin adsorbed to solid substrata with different wettabilities in a parallel plate flow cell (1990)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 24 (1990), S. 1599-1614 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: In this article we studied the adsorption of serum albumin to substrata with a broad range of wettabilities from solutions with protein concentrations between 0.03 and 3.00 mg · mL-1 in a parallel-plate flow cell. Wall shear rates were varied between 20 and 2000 s-1. The amount of albumin adsorbed in a stationary state was always highest on PTFE, the most hydrophobic material employed and decreased with increasing wettability of the substrata. Increasing stationary amounts of adsorbed albumin were observed with increasing wall shear rates at the lowest protein concentration. Inverse observations were made at the highest protein concentration. Transmission electron micrographs of replicas from the albumin-coated substrata showed that proteins were mostly adsorbed in islandlike structures on the hydrophobic substrata. The tendency to form islandlike structures was shear rate- and concentration-dependent and disappeared gradually going to more hydrophilic substrata. On glass, the most hydrophilic material employed, a homogeneous, well distributed, fine knotted, reticulated structure was found. In conclusion, this study demonstrates that both the amount of adsorbed albumin as well as the surface structure of the adsorbed proteins are regulated by the substratum wettability. This observation may well account for the fact that substratum properties can be transferred by an adsorbed protein film to the interface with adhering cells or microorganisms.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820241205
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  • 9
    Electronic Resource
    Electronic Resource
    Development and use of a parallel-plate flow chamber for studying cellular adhesion to solid surfaces (1992)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 26 (1992), S. 725-738 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A parallel-plate flow chamber is developed in order to study cellular adhesion phenomena. An image analysis system is used to observe individual cells exposed to flow in situ and to determine area, perimeter, and shape of these cells as a function of time and shear stress. With this flow system the behavior of human fibroblasts spread on glass is studied when exposed to an increasing laminar flow. The flow system appears to be well-suited for following individual cells during detachment. After 75 to 90 min, at a shear stress of 350 dynes/cm2, more than 50% of the spread cells are detached from the surface. Cells with higher spreading areas stay longer at the glass surface. Cells round up before detaching. Sometimes the cell body is attached to the substratum through a thin filament during detachment. At the scanning electron microscopy level numerous filopodial extensions are observed. Cell material could only rarely be observed at the light or scanning electron microscopic level on the substratum once a cell was detached.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820260604
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  • 10
    Electronic Resource
    Electronic Resource
    XPS determination of the thickness of adsorbed mouthrinse components on dental enamel (1990)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 15 (1990), S. 344-346 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: In this paper, the stationary charging voltage of human dental enamel samples due to photoelectron ejection in an x-ray photoelectron spectrometer is related to the amount of material adsorbed from commercially available mouthrinses and the adsorbed layer thickness. A clear relationship was observed between the charging voltage versus the C/Ca elemental surface concentration ratio, taken as a measure of the amount of adsorbed material. Consequently, a similar relationship was found between charging versus adsorbed layer thickness.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740150508
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