Multivariate analysis of surface physico-chemical properties controlling biofilm formation on orthodontic adhesives prior to and after fluoride and chlorhexidine treatment

2006 ◽  
Vol 78B (2) ◽  
pp. 401-408 ◽  
Author(s):  
Mervyn Y. H. Chin ◽  
Andrew Sandham ◽  
Jonathan Pratten ◽  
Joop De Vries ◽  
Henny C. van der Mei ◽  
...  
Keyword(s):  
Multivariate Analysis ◽  
Biofilm Formation ◽  
Chemical Properties ◽  
Orthodontic Adhesives ◽  
Physico Chemical

scholarly journals Elasticity and physico-chemical properties during drinking water biofilm formation

Biofouling ◽  
2011 ◽  
Vol 27 (7) ◽  
pp. 739-750 ◽  
Author(s):  
Yumiko Abe ◽  
Pavel Polyakov ◽  
Salaheddine Skali-Lami ◽  
Grégory Francius
Keyword(s):  
Drinking Water ◽  
Biofilm Formation ◽  
Chemical Properties ◽  
Physico Chemical

scholarly journals Preliminary Evaluation of the Safety and Probiotic Potential of Akkermansia muciniphila DSM 22959 in Comparison with Lactobacillus rhamnosus GG

2020 ◽  
Vol 8 (2) ◽  
pp. 189 ◽  
Author(s):  
Autilia Cozzolino ◽  
Franca Vergalito ◽  
Patrizio Tremonte ◽  
Massimo Iorizzo ◽  
Silvia J. Lombardi ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Biofilm Formation ◽  
Lactobacillus Rhamnosus ◽  
Chemical Properties ◽  
Preliminary Evaluation ◽  
Lactobacillus Rhamnosus Gg ◽  
Akkermansia Muciniphila ◽  
Probiotic Potential ◽  
Physico Chemical ◽  
First Time

In this study, for the first time, we examined some of the physico-chemical properties of the cell surface of Akkermansia muciniphila DSM 22959, comparing it with those of Lactobacillus rhamnosus GG—one of the most extensively studied probiotic microorganisms. In particular, hydrophobicity, auto-aggregation, co-aggregation, and biofilm formation were investigated. In addition, antibiotic susceptibility, co-culture, and antimicrobial activity of the two strains were compared. Hydrophobicity was evaluated using xylene and toluene, showing that A. muciniphila DSM 22959 possessed moderate hydrophobicity. A. muciniphila showed a faster and higher auto-aggregation ability than Lb. rhamnosus GG, but a lower aptitude in biofilm formation. In the co-aggregation test, the best performance was obtained by Lb. rhamnosus GG. Regarding the susceptibility to antibiotics, the differences between the two strains were remarkable, with A. muciniphila DSM 22959 showing resistance to half of the antibiotic tested. Interesting results were also obtained with regard to the stimulating effect of Lb. rhamnosus GG on the growth of A. muciniphila when co-cultured.

Grouping soils of the Montreal Lowlands (Quebec) according to fertility and P sorption and desorption characteristics

2001 ◽  
Vol 81 (1) ◽  
pp. 71-83 ◽  
Author(s):  
M L Leclerc ◽  
M C Nolin ◽  
D. Cluis ◽  
R R Simard
Keyword(s):  
Multivariate Analysis ◽  
Soil Fertility ◽  
Ammonium Oxalate ◽  
Chemical Properties ◽  
Soil Survey ◽  
Classification Model ◽  
Soil P ◽  
P Sorption ◽  
Physico Chemical ◽  
Extractable P

Soil tests P (STP) developed to estimate P fertilizer needs and designed to produce optimal economic crop yields, are often not well suited to assess potential environmental impact of fertilization practices. The objective of this study was to develop interpretative soil groupings of the Montreal Lowlands area (MLA) based on soil physico-chemical properties and on soil P sorption and desorption characteristics. Soil P sorption and desorption characteristics together with STP may help in evaluating potential risks of soil P addition. Sixty-six soil types (phases of soil series based on surface texture) were selected as representative soils of the study area. Twenty-seven soil properties were used, including Mehlich-3 extractable P and Al, ammonium-oxalate extractable P, Fe and Al, P sorption index (Psi) and Bray-2 extractable P(BR2P). Multivariate analysis was applied to generate clusters and interpret soil groupings. Principal components analysis yielded two components related: (1) to soil inherent fertility (texture) and (2) to P sorption capacity and desorption intensity. The Ward's clustering method was then applied to the first two component scores. Five soil fertility groups were obtained. Multiple discriminant analysis proposed a classification model using a small subset of variables. Five variables were selected among the soil survey characteristics for discriminating soil groups: clay content, pH measurement in water, cation exchange capacity, BR2P and ammonium-acetate extractable Mg. Adding Psi in the model improved the classification correctness. The results of this study indicate that physico-chemical properties of the surface layer used together with soil P sorption-desorption characteristics contributed to the development of an interpretative grouping that may also be useful to assess vulnerability to water contamination by P. Key words: Soil behavior, soil fertility groups, multivariate analysis techniques

scholarly journals Hyaluronic Acid Reduces Bacterial Fouling and Promotes Fibroblasts’ Adhesion onto Chitosan 2D-Wound Dressings

2020 ◽  
Vol 21 (6) ◽  
pp. 2070 ◽  
Author(s):  
Ilaria Silvestro ◽  
Mariangela Lopreiato ◽  
Anna Scotto d’Abusco ◽  
Valerio Di Lisio ◽  
Andrea Martinelli ◽  
...  
Keyword(s):  
Wound Healing ◽  
Hyaluronic Acid ◽  
Biofilm Formation ◽  
Transmission Rate ◽  
Wound Care ◽  
Chemical Properties ◽  
Infectious Complications ◽  
Wound Dressings ◽  
Physico Chemical ◽  
Wound Healing Activity

Wound healing is a dynamic process that can be seriously delayed by many factors including infectious complications. The development of dressings with intrinsic wound healing activity and/or releasing bioactive compounds may help with addressing such an issue. In this study, hyaluronic acid (HA) at different percentages (1–35%) was used to modify chitosan (CS) biological and physico-chemical properties in order to obtain 2D-matrices able to promote healing and protect from infection. HA incorporation in the CS matrix decreased film transparency and homogeneity, but improved film water uptake and surface wettability. The water vapor transmission rate (WVTR) increased up to a 5% HA content, where it reached the highest value (672 g/m2 day), and decreased for higher HA contents. At all of the tested HA concentrations, HA affected mechanical properties providing matrices more flexible than pure CS with benefit for wound care. Pure CS films permitted S. epidermidis adhesion and biofilm formation. That was not true for CS/HA matrices, where HA at concentrations equal to or greater than 5% was able to avoid S. epidermidis adhesion. Fibroblasts adhesion also took benefit from the HA presence in the film, especially at 5% content, where the best adhesion and proliferation was found.

Decoration of specific sites on freeze-fractured membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 140-141
Author(s):  
H. Gross ◽  
H. Moor
Keyword(s):  
Pure Water ◽  
Freeze Fracture ◽  
Chemical Properties ◽  
Surface Forces ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate ◽  
Physico Chemical ◽  
Water Of Hydration ◽  
Small Container ◽  
Binding Forces

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.

Physico-Chemical Properties of Recombinant Desulphatohirudin

1990 ◽  
Vol 63 (03) ◽  
pp. 499-504 ◽  
Author(s):  
A Electricwala ◽  
L Irons ◽  
R Wait ◽  
R J G Carr ◽  
R J Ling ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Chemical Properties ◽  
Alpha Helix ◽  
Apparent Molecular Weight ◽  
Correlation Spectroscopy ◽  
Nmr Studies ◽  
Recombinant Hirudin ◽  
Physico Chemical ◽  
Recombinant Molecule

SummaryPhysico-chemical properties of recombinant desulphatohirudin expressed in yeast (CIBA GEIGY code No. CGP 39393) were reinvestigated. As previously reported for natural hirudin, the recombinant molecule exhibited abnormal behaviour by gel filtration with an apparent molecular weight greater than that based on the primary structure. However, molecular weight estimation by SDS gel electrophoresis, FAB-mass spectrometry and Photon Correlation Spectroscopy were in agreement with the theoretical molecular weight, with little suggestion of dimer or aggregate formation. Circular dichroism studies of the recombinant molecule show similar spectra at different pH values but are markedly different from that reported by Konno et al. (13) for a natural hirudin-variant. Our CD studies indicate the presence of about 60% beta sheet and the absence of alpha helix in the secondary structure of recombinant hirudin, in agreement with the conformation determined by NMR studies (17)

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