Roles of pathway-based models and their contribution to the redesign of health-care systems

Care pathways provide a practical analytical tool that encompasses both organizational efficiency and individual patients'care. In the UK, constructing the care pathway has been a recommended starting point for the re-design of health-caresystems. This paper examines the re-design cycle for health-care systems and looks at the role of pathway-basedmodels in the design and operation phases of the cycle. In addition, the models provide further benefits for communicatingrecommended practice and audit of care and outcomes. The models span the classic care pathway with extensions tosimulation modelling. An example of the use of care pathways in the re-design of an emergency department is used forillustration. This study shows the role of pathway models as: a tool for re-design, a catalyst for enhancing communicationand as a repository for audit information. The final role of a tool for modelling contingencies was not implemented. Fromthe example it can be concluded that sophisticated models can be useful, in some applications; however, the simplerapproaches may often be the best, offering rapid, transparent recommendations based on a multidisciplinary approach

Bone Tissue Response to Porous and Functionalized Titanium and Silica Based Coatings

Background: Topography and presence of bio-mimetic coatings are known to improve osseointegration. The objective of this study was to evaluate the bone regeneration potential of porous and osteogenic coatings. Methodology: Six-implants [Control (CTR); porous titanium coatings (T1, T2); thickened titanium (Ti) dioxide layer (TiO2); Amorphous Microporous Silica (AMS) and Bio-active Glass (BAG)] were implanted randomly in tibiae of 20-New Zealand white rabbits. The animals were sacrificed after 2 or 4 weeks. The samples were analyzed histologically and histomorphometrically. In the initial bone-free areas (bone regeneration areas (BRAs)), the bone area fraction (BAF) was evaluated in the whole cavity (500 mm, BAF-500), in the implant vicinity (100 mm, BAF-100) and further away (100–500 mm, BAF-400) from the implant. Bone-to-implant contact (BIC-BAA) was measured in the areas where the implants were installed in contact to the host bone (bone adaptation areas (BAAs)) to understand and compare the bone adaptation. Mixed models were used for statistical analysis. Principal Findings: After 2 weeks, the differences in BAF-500 for different surfaces were not significant (p.0.05). After 4 weeks, a higher BAF-500 was observed for BAG than CTR. BAF-100 for AMS was higher than BAG and BAF-400 for BAG was higher than CTR and AMS. For T1 and AMS, the bone regeneration was faster in the 100-mm compared to the 400-mm zone. BIC-BAA for AMS and BAG was lower after 4 than 2 weeks. After 4 weeks, BIC-BAA for BAG was lower than AMS and CTR. Conclusions: BAG is highly osteogenic at a distance from the implant. The porous titanium coatings didn’t stimulate bone regeneration but allowed bone growth into the pores. Although AMS didn’t stimulate higher bone response, it has a potential of faster bone growth in the vicinity compared to further away from the surface. BIC-BAA data were inconclusive to understand the bone adaptation.status: publishe

Existence of a Tribo-Modified Surface Layer on SBR Elastomers: Balance Between Formation and Wear of the Modified Layer

In most of the tribological contacts, the composition and tribological properties of the original interface will change during use. The tribo-films, with modified properties compared to the bulk, are dynamic structures that play a significant role in friction. The existence of a tribo-modified surface layer and its importance on the overall friction of elastomers has been shown both theoretically and experimentally before. The characteristics of the modified surface layer deserve specific attention since the tribological properties of elastomers in contact with a rough counter-surface are determined by these modified surfaces together with the properties of bulk of the material. Both the formation of the modified layer and the break down (wear) of it are of importance in determining the existence and thickness of the tribo-modified layer. In this study, the importance of the wear is emphasized by comparing two styrene butadiene rubber-based elastomers in contact with a granite sphere. A current status of perception of the removal and the stability of the modified surface layers on rubbers is introduced as well as experimental work related to this matter and discussion within literature. Pin-on-disk friction tests are performed on two SBR-based samples in contact with a granite sphere under controlled environmental conditions to form the modified surface layer. Although the hysteresis part of the friction force which has a minor contribution in the overall friction is not markedly different, the total measured friction coefficient differs significantly. Mechanical changes both inside and outside the wear track are determined by atomic force microscope nano-indentations at different timescales to examine the modified surface layer on the test samples. The specific wear rates of the two tribo-systems are compared, and the existence of the modified surface layer, the different measured friction coefficient and the running-in distances toward steady-state friction are explained considering different wear rates. A conceptual model is presented, correlating the energy input into the tribo-system and the existence of a modified surface layer

Alterations of thorium oxalate morphology by changing elementary precipitation conditions

Oxalates of actinide elements are widely used in research and industry mainly due to their low solubility in aqueous solution and easy conversion to oxide. Although thorium oxide is worldwide mostly produced by the oxalate precipitation and conversion route, the powder morphology obtained through this process is known to inhibit the packing and sintering step of the pellet production. The presented work investigates the effects of oxalate precipitation conditions on the final powder morphology. Among the precipitation conditions considered are: pH of the thorium feed solution, concentration, temperature and the order of addition (thorium solution in oxalic acid solution and vice versa) known as reverse/direct strike. Herein, we show that the morphology of the final oxalate depends significantly on the above mentioned precipitation parameters.status: publishe

Morphology dependent sintering path of nanocrystalline ThO2

status: publishe

Atmospheric plasma inactivation of biofilm-forming bacteria for food safety control

The ability of atmospheric pressure glow discharges (APGD) to inactivate microorganisms has been demonstrated in a number of previous studies. However, most of this work has been performed using microorganisms that do not form biofilms and with the microorganisms supported on abiotic surfaces that discourage cell growth. When microorganisms attach to the surface of a food, they can extract nutrients from the food and proliferate at the surface. Often this growth takes the form of biofilms which comprise three-dimensional (3-D) networks of polysaccharides that attach microorganisms to surfaces and serve to protect them from external stresses; fresh foods, such as salad crops, frequently harbor biofilms. We believe that the use of APGD offers a potential for inactivating microorganisms on the surface of fresh foods that cannot be readily treated by other methods without inducing unacceptable changes to these foods. As a first step toward a full evaluation of the viability of the APGD technology for food safety control, we consider in this paper two key issues, namely: 1) whether atmospheric glow discharges can inactivate biofilm-forming microorganisms and 2) whether plasma treatment causes significant discoloration to food surfaces. Using the biofilm-forming bacterium Pantoea agglomerans and bell peppers (Capsicum annuum) as a typical example of plant tissue, we show that atmospheric He-O/sub 2/ plasmas can be effective inactivation agents without causing unacceptable levels of discoloration to the peppers, and that furthermore they are superior to the use of low-pressure ultraviolet sources