Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Influence of Interparticle Interactions on Blocked Areas and Desorption during Particle Deposition to Glass in a Parallel Plate Flow Chamber (1995)
    s.l. : American Chemical Society
    Langmuir 11 (1995), S. 327-333 
    Details
    ISSN: 1520-5827
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/la00001a055
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The effect of topically applied fluorides on the surface free energy of human dentin (1984)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 19 (1984), S. 0 
    Details
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The surface free energy γs of human dentin treated with sodium fluoride, acidulated phosphate fluoride, and aminfluoride solutions has been determined by means of contact angle measurements. Application of an aminfluoride solution slightly increased the total surface free energy from 75 to 80 erg. cm−2. The γs values of dentin after a neutral sodium fluoride application decreased to 62 erg. cm−2. APF solutions hardly influenced the surface free energy γs. This study showed that fluoride applications change the surface free energy of human dentin.Extrapolation of the results of this study and the in vitro results on cell spreading indicated that aminfluoride applications might be favorable for the reattachment of periodontal tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0765.1984.tb01310.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Adhesion of stainable, calcium–rich deposits on substrata with different surface free energies (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of clinical periodontology 16 (1989), S. 0 
    Details
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract Calculus plays an important role in chronic inflammatory periodontal disease and tooth loss. Patients can suffer from calculus formation despite good oral hygiene. The strength of adhesion between calculus and the enamel surface, though not determinant for the formation of calculus itself, determines whether calculus remains on the teeth during eating and toothbrushing. In this study, the amount and the strength of adhesion of calcium-rich deposits formed in vivo on different materials are related to substrate surface free energies (sfe). In 4 beagle dogs, fenestrated crowns were made on the upper fourth premolars. Smooth facings of glass (sfe 120 mJ·m-2), polished bovine enamel (sfe 85 mJ·m-2), polymethylmethacrylate (PMMA sfe 56 mJ·m-2) and polytetafluorethylene (PTFE sfe 20 mJ·m-2) were inserted in the crowns for 1, 3, 7, 14 or 28 days. The amount of deposit was evaluated both gravimetrically and planimetrically using Alizarin Red S for staining. Adhesion of calcium-rich deposits was evaluated planimetrically by studying their removal in a brushing machine. Dry weight increased linearly with time (approximately 0.18 mg·cm-2 per day) and was slightly less on PTFE than on the other materials. After 1 to 3 days, staining already revealed a 100% coverage by calcium-rich deposits. The number of strokes required to reduce the planimetric scores by 63% was extremely small on PTFE and PMMA and related with substrate surface free energies. This study shows that a possible way to reduce calculus formation in vivo is to decrease the surface free energy of the enamel using appropriate surfactants in, e.g., toothpastes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-051X.1989.tb01666.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Biosurfactants from thermophilic dairy streptococci and their potential role in the fouling control of heat exchanger plates (1996)
    Springer
    Journal of industrial microbiology and biotechnology 16 (1996), S. 15-21 
    Details
    ISSN: 1476-5535
    Keywords: biosurfactants ; thermophilic streptococci ; heat exchanger ; Streptococcus thermophilus ; adhesion ; fouling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Recent work on biosurfactant release by thermophilic dairy streptococci is reviewed. There is a suggestion thatStreptococcus thermophilus isolates may release biosurfactants that stimulate detachment of already-adhering cells and leave an anti-adhesive coating on a substratum. A previously published rapid screening method is described for the identification of biosurfactant-releasing microorganisms, and growth medium supplements to enhance biosurfactant release by thermophilic dairy streptococci are reported. New experimental work described includes the isolation and purification of biosurfactants from dairy isolates by thin layer chromatography. Many compounds isolated were extremely surface-active and reduced the water surface tension to values around 30 mJ m−2 at a concentration of 10 mg ml−1. Most importantly, the thin layer chromatograms of various isolates resembled each other, and an adsorbed purified compound from one isolate retarded the deposition to glass of another isolate by a factor of two. Provided our findings implicate that these biosurfactants could also be adsorbed to heat exchanger plates in pasteurizers and thereby retard colonization by thermophilic streptococci, these compounds may have major economic implications. Further work is required, however.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01569916
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Initial adhesion and surface growth of Pseudomonas aeruginosa on negatively and positively charged poly(methacrylates) (1999)
    Springer
    Journal of materials science 10 (1999), S. 853-855 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract The infection risk of biomaterial implants is determined by an interplay of bacterial adhesion and surface growth of the adhering organisms. In this study, we compared initial adhesion and surface growth of Pseudomonas aeruginosa AK1 (zeta potential −7 mV) on negatively charged (PMMA/MAA, zeta potential −18 mV) and positively charged (PMMA/TMAEMA-Cl, zeta-potential +12 mV) methacrylate copolymers in situ in a parallel plate flow chamber. Initial adhesion was measured using phosphate-buffered saline and subsequent surface growth of the adhering bacteria using nutrient broth as growth medium. Initial adhesion was twice as fast on the positively charged methacrylate than on the negatively charged copolymer. Surface growth, however, was absent on the positively charged copolymer, while on the negatively charged methacrylate the number of bacteria increased exponentially during surface growth with a generation time of 32 min. From the results of this study it can be concluded that positively charged biomaterial surfaces might show reduced risks of biomaterials-centred infections, despite being more adhesive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008989416939
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...