Search results for "CONTACT"

Histoincompatibility reactions in the hydrocoral Millepora dichotoma

1983

The xenogeneic- and allogeneic immunological specificity of the hydrocoral Millepora dichotoma has been investigated. Xenogeneic histoicompatibility reactions have been observed between this hydrocoral and a series of species belonging to the Demospongiae and to the Anthozoa (both Hexacorallia and Octocorallia). The xenogeneic histoincompatibility reactions proceed in the following sequence: (a) Species-unspecific sensitization; (b) necrosis formation, which is very likely due to an autolytic process; (c) callus formation, due to an hyperplastic growth of stolons; and (d) formation of a contact barrier in form of a barrier layer or a restored stolonial layer. Allogeneic histoincompatibility…

Repeatability of in vitro power profile measurements for multifocal contact lenses

2015

Abstract Purpose To evaluate the repeatability of an optical device (NIMO TR1504, Lambda-X, Belgium) for measuring multifocal contact lens power profiles. Methods The NIMO TR1504 was used to measure power profiles 30 times for each of 10 different contact lenses from 4 major companies. All contact lenses were labelled as −3 D for distance vision; half were for high addition and half for low addition. The optical zone in all measurements was set to 3-mm radius. For each lens, the median power profile and the residuals of the 30 measurements were calculated. The 95% confidence bands and two indices that summarize measurement errors were calculated: the repeatability limit and an index of repe…

Antibacterial and antifungal effects of soft contact lens disinfection solutions.

1998

To study the antibacterial and antifungal effects of soft contact lens disinfection solutions.Eight contact lens disinfection solutions containing hydrogen peroxide or biguanides or polyquad compounds were evaluated with respect to their ability to disinfect a saline solution experimentally contaminated with different bacteria and with a fungus. We used cultures in blood Agar, MuellerHinton agar and Saboureaud's agar to identify the bacterial and fungal growth following 14 h of exposure to the disinfection solutions.Hydrogen peroxide, DYMED and polyhexamide solutions prevented the growth of the four bacteria studied. The solution containing biguanide prevented the growth of Escherichia coli…

pH of multipurpose contact lens solutions over time

1998

The pH of nine different brands of multipurpose contact lens solutions available in Spain was determined over a period of 32 days after opening the bottles. Five bottles of nine solutions were used, each of which was buffered and obtained from different manufacturers. The pH measurements were taken using a micropH 2002 Crison pH-meter (accuracy +/- 0.001 pH units). Each solution was measured three times daily over the test period using 10-ml samples taken from the same container. Fluctuations in pH over time were observed but these were within the range of ocular comfort. The average pH of all the solutions tested proved to be between 6.99 and 7.56.

Comparative study of pH for different saline and multi-purpose contact lens solutions.

1997

In this study, we determined the pH of different saline and multipurpose contact lens solutions available on the Spanish market. We examined 10 samples of 14 solutions, seven of which are saline solutions and seven multipurpose ones, from different manufacturers. Both types of solution were found to have significant variations in pH, with values ranging from 6.70 to 7.57 for the saline solutions and 6.84 to 7.63 for the multipurpose solutions. We concluded that the solutions should not affect the ocular physiological performance because their pH values are within the buffering capacity of the eye.

The impact of daily disposable soft contact lens wear on tear film surface quality over a three month period

2017

mplicit Identification of Contact Parameters in a Continuous Chain Model

2011

Accurate contact modeling is of great importance in the field of dynamic chain simulations. In this paper emphasis is on contact dynamics for a time-domain simulation model of large chains guided in a closed loop track. The chain model is based on theory for unconstrained rigid multibody dynamics where contact within the chain and with the track is defined through continuous point contacts using the contact indentation and rate as means. This paper presents an implicit method to determine contact parameters of the chain model through the use of none gradient optimization methods. The set of model parameters are estimated by minimizing the residual between simulated and measured results. The…

Etude d'un emmanchement fretté compte tenu de l'effet combiné des défauts de forme et d'état de surface

2012

The main purpose of this thesis is to present two contributions in the field of shrink fitassembly taking into account the defects of form and roughness surfaces. The first contributionconcerns the study of the influence of the defect forme on the characteristics of shrinked assemblyusing an approach based on finite element modeling. We found that this defect has a significantinfluence on the resistance of the assembly. The work already done in the laboratory of mechanicsat the University of Bourgogne have been confirmed. In the second contribution, we proposed tointegrate the surface defects (roughness) by creating a homogenized finite element interface. Thistechnique has facilitated the m…

Antimicrobial activity and enterococcus faecalis biofilm formation on chlorhexidine varnishes.

2011

Objective: To evaluate, in vitro, the antimicrobial activity and biofilm formation of three chlorhexidine varnishes in four Enterococcus faecalis strains: E. faecalis ATCC 29212, E. faecalis EF-D1 (from failed endodontic treatment), E. faecalis 072 (cheese) and E. faecalis U-1765 (nosocomial infection), and one Enterococcus durans strain (failed endodontic treatment). Study Design: The direct contact test was used to study the antimicrobial activity. Bacterial suspensions were exposed for one hour to EC40, Cervitec (CE) and Cervitec Plus (CEP) varnishes. “Eradication” was defined as 100% bacterial kill. The formation of enterococci biofilms was tested on the surface of the varnishes after 2…

Biological and physico-chemical properties of new root canal sealers

2018

Background The purpose of the present study was to compare the biological and the physico-chemical properties of bioceramic-based root canal sealers, calcium hydroxide-based, MTA-based and epoxy resin-based root canal sealers. Material and methods Two bioceramic-based sealers, one calcium hydroxide-based sealer, one MTA-based sealer and two epoxy resin-based sealers were tested. Results EasySeal and MTA Fillapex showed severe citotoxic activity, AH Plus and SealapexTM moderate cytotoxicity, BioRoot™ RCS and TotalFill BC Sealer were both cytocompatible. Except for TotalFill BC Sealer, all root canal sealers caused inhibition zones when tested with E. faecalis. The highest inhibition zone was…