Influence of electrostatic particle interactions on the properties of particulate coatings of titanium dioxide.

HYPOTHESIS: Particulate coatings are used in a wide range of technical applications. The application affecting properties of these coatings depend strongly on the structure formation along the production process. Thus, primary and secondary particle size, size distribution, particle morphology as well as the particle-particle and particle-fluid interactions of the used formulation affect the resulting coating properties. EXPERIMENTS: In this investigation titanium dioxide particles were dispersed in ethanol with a stirred media mill and stabilised electrostatically. Subsequently, the suspension was destabilised to reach specific pH* values and processed into coatings by dip coating. The influence of the pH* value of the suspension on the suspension's properties such as viscosity, agglomerate size and zeta potential and on its application properties such as coating thickness, micro-mechanical properties, abrasion resistance, gloss, roughness and adhesion was examined. FINDINGS: The electrostatic particle interactions show a significant influence on the structure formation as well as on the properties of nanoparticulate coatings. The coating properties are affected by the coating structures on micro-, meso- or macroscopic scale. Selective coating properties were related to the coating structure using the theoretical model of Rumpf. Besides other important process and formulation parameters, for the production of homogeneous, functional coatings with the desired properties a precise adjustment of the particle interactions is necessary.

Hospital paediatricians' workflow interruptions, performance, and care quality: a unit-based controlled intervention.

OBJECTIVE: Frequent workflow interruptions jeopardise clinicians' efficiency and quality of clinical care. We sought to determine the effect of a documentation-assistant intervention. Our hypothesis was that the expected decrease of workflow interruptions enhances paediatricians' performance and simultaneously improves patients' perceived quality of care. METHODS: This was a controlled intervention study with data collected before and after the intervention at a University Children's Hospital. For the intervention, a documentation assistant was assigned to an inpatient ward. The main outcome measures were workflow interruptions, paediatricians' performance, as well as patients' perceived quality of care. Workflow interruptions were assessed via standardised expert observations. Paediatricians' evaluated their performance in terms of productivity, quality, and efficiency. Additionally, standardised patients' reports on perceived quality of care were collected. RESULTS: For paediatricians in the intervention ward, workflow interruptions decreased significantly from 5.2 to 3.1 disruption events per working hour (decrease in the control unit was from 3.8 to 3.1). Furthermore, paediatricians reported at follow-up significantly enhanced productivity, quality, and efficiency. Similarly, patients' ratings of care quality improved significantly over time. In multivariate analyses, we found substantial changes attributable to the intervention: for all three outcomes, we found a significant interaction effect of the intervention over study time. CONCLUSIONS: The intervention streamlined paediatricians' workflow, improved day-to-day functioning of the ward, and enhanced organisational efficiency and delivery of paediatric care. Future studies should investigate potential influences between the reduction of workflow interruptions, paediatricians' perceived performance, and patient-related outcomes in quality and efficiency of paediatric care.