In an effort to re-establish tissue with odontogenic potential in the pulp space of immature permanent teeth, stimulated human dental pulp stem/progenitor cells (hDPSCs) have shown potential to differentiate and form mineralized matrix, marked by high expression of dentin sialophosphoprotein (DSPP) and osteocalcin (OCN). Bacterial by-products have been shown to adversely affect cell differentiation. This study investigated the effect of P. gingivalis, a putative endodontic pathogen, and blockage of its host recognition on hDPSCs. Stimulated hDPSCs were exposed to varying concentrations of P. gingivalis by-product and gene expression of DSPP and OCN was measured. Cells were exposed to TLR2 blocking agents prior to exposure to the by-product. P. gingivalis affected dose-dependent suppression of the measured gene expression. Blockade of TLR2 inhibited the by-product derived suppression of gene expression. The immune-potential of by-product was confirmed to be detrimental to the differentiation of hDPSCs, and this effect could be moderated by TLR2-blockade.

Metso develops (among many other things) refiners. The refiner grinds the wood chips intopulp. The grinding is done by segments that are placed on a rotor inside the refiner hosing.In time this segments wear and needs to be replaced.When changing refiner segments or performing service to the refiner the rotor needs to berotated. To perform the rotating motion today the overhead crane is used. This procedure isboth impractical, dangerous and takes precious time from the overhead crane. Because ofthis Metso wanted to create a new way to rotate the rotor.The aim of this thesis is to create a tool or equipment which can be used to rotate therefiner rotor and can be installed as an upgrade on all Metso refiner models.The proposed design is driven with a 1.1 kW electrical motor and a gearbox with a gear ratioof approximately 1:217. The torque is transferred from the outgoing gearbox shaft to therefiner shaft with the help of gearwheels. To connect the gearbox gearwheel with the refinershaft gearwheel, the gear motor has to be moveable in a radial direction. This is done by themeans of two shafts that glides in four bushings. On the gearbox shaft a gearwheel with 120mm of face width is mounted. The large face width is used to take up the axial movement ofthe refiner shaft.The proposed concept fulfills all of the demands set in the pilot study. The design is goodbecause of the low cost and straight forward design that is easy to build and simple to use.The disadvantage is that the equipment is a bit large and heavy, but as stationary equipmentthis should not be a problem.

No description available.

Thesis (Ph. D.) in Chemistry--University of Maine, 2003. / Includes vita. Includes bibliographical references (leaves 103-115).

Thesis (Ph. D.) in Chemical Engineering--University of Maine, 2003. / Includes vita. Includes bibliographical references (leaves 155-160).

Thesis (M.Sc.(Odontology))--University of Pretoria, 2009. / Includes bibliographical references.

No description available.

The main purpose of this study was to determine the effect of contour height on the passage ratio of pulp through screen apertures, and determine which operating variable has the greatest affect on screen performance. In addition, a freeness model was to be developed, in hopes of helping to predict the freeness drop between feed and accepts. The study was conducted at The University of British Columbia (UBC) using a laboratory scale pressure screen. Slot velocity, feed consistency and contour height were the changing variables. Samples were collected from which passage ratio, freeness, fibre length and coarseness were determined. From the studies conducted it was found that slot velocity had the greatest influence on the screen operation. As the slot velocity increased a greater force was applied to the fibre to help push it through the screen aperture. However, this increase in slot velocity decreases the fractionation ability (separation of fibres into different lengths) of the screen. The second most important variable was the contour height. The main function of the contour height is to disrupt the flow of thick stock at the wall of the screen and allow for unhindered movement of fibre to the screen wall. The greater the contour height is, the greater the passage ratio (pulp fibre passing through screen). However, there is a decrease in fractionation. The third most important factor was the feed consistency. At low feed consistencies there is less crowding in the screen. Less crowding leads to more loosely-formed flocs, which are easier for the contour height and the rotor to dissipate and thus leads to unhindered movement. Thicker feed stock has a negative effect on passage A Freeness model was developed that showed that freeness had a power law relationship to passage ratio. The passage ratio was raised to a constant B, which is a function of the contour height and the feed consistency.

No description available.

No description available.