The preparation and characterization of alumina membranes with ultra-fine pores : Part 3. The permeability for pure liquids

This paper reports on the permeability of alumina membranes with pore diameters of a few nanometers for pure liquids. It appears that the volume flux corrected for viscosity differences depends on the type of permeant. It decreases in the order water, hexane, ethanol, s-butanol. The hydraulic resistance defined as the reciprocal permeability) of supported membranes can be taken as the sum of the hydraulic resistance of the membrane and that of the support. This implies that the membrane material does not penetrate the pores of the support significantly. The Kozeny—Carman constant for alumina membranes calcined at 800°C amounts to 13.3±2. This value is much higher than the commonly found value of 5. This can be explained by taking into account the plate shape of the crystallites forming the membrane, resulting in a microstructure with a high value for the tortuosity

The preparation and characterization of alumina membranes with ultra-fine pores : Part 4. Ultrafiltration and hyperfiltration experiments

The rejection characteristics of three types of alumina membranes for polyethylene glycol (PEG) polymers and dextrans soluted in water have been investigated. If the temperature at which the membranes are treated is increased, the pore size increases and as a result the cut-off value also increases. The Al2O3-400 membrane (i.e., the membrane treated at 400°C) exhibits a cut-off value of 2,000 for PEG while that of an Al2O3-800 membrane is about 20,000. Both Al2O3-500 and Al2O3-800 membranes show rejections higher than 80% for the dextrans investigated. The rejection behaviour is compared with literature data on Nuclepore membranes. The performance of the alumina membranes is compared with that of other inorganic membranes. Low molecular weight solutes show only small rejection values solar, although high values are reported in the literature for Vycor glass membranes with pores of similar size

The preparation and characterization of alumina membranes with ultrafine pores 2. The formation of supported membranes

Supported γ-A12O3 membranes are prepared by a dipping procedure. According to this method, a capillary pressure drop is created by bringing a microporous ceramic support into contact with a boehmite (γ-A1OOH) sol. This pressure drop forces the dispersion medium of the sol to flow into the dry part of the support. The sol particles are concentrated at the entrance of the pores and a gel is formed. This gel can be dried and calcined to form a crack-free alumina membrane with pores measuring only a few nanometers, if the membrane thickness after calcination is about 5 μm or less. The gel formation process can be quantitatively well described with the slibcasting model. The observations that the membrane thickness increases linearly with the square root of the dipping time and that the casting rate increases if the sol concentration increases, the pore size of the support decreases or the gelling concentration decreases, are all in accordance with this slibcasting model

The Care Sport Connector in the Netherlands

Introduction To stimulate physical activity (PA) and guide primary care patients towards local PA facilities, Care Sport Connectors (CSC) (in Dutch Buurtsportcoach), to whom a broker role has been ascribed, were introduced in 2012. This function is new, and to our knowledge no study has yet explored a broker role and its impact on improving intersectoral collaboration between both sectors. The aim of this thesis was to explore CSCs’ role and impact in connecting the primary care and the PA sector. Method This thesis employed a multiple case study design in which 15 CSCs from nine municipalities spread over the Netherlands were followed in their work from 2014 to the end of 2016. Different data collection methods were used (literature review, interviews, focus groups, document analysis, and questionnaires), and perspectives of different stakeholders (policymakers, professionals, CSCs) on different levels (policy and community) were taken into account (Chapter 2). Results The connection between the primary care and the PA sector: a chain approach The connection between both sectors can be characterised as a chain in which CSCs guide the target group towards PA facilities after referral by primary care professionals or their own recruitment. In this connection CSCs fulfilled three roles - broker, referral, and organiser – which did not change over time (Chapter 4 and 5). Barriers at system and sector level hinder the established connection Barriers related to the primary care (lack of time, money and knowledge) and the PA sector (lack of suitable PA activities and adequate instructors) are currently hindering the connection between both sectors (Chapter 4 and 6). Barriers related to the collaboration between both sectors, like cultural differences and different interests as identified in our literature review (Chapter 3) were not identified. The importance of an integral approach for CSCs and the connection between both sectors An integral approach to structural embed CSCs (Chapter 7) seemed to influence CSCs’ work and subsequently their impact. CSCs working in municipalities who structurally embedded CSCs only at the PA sector, connected both sectors mostly by jointly organising activities. CSCs working in municipalities who adopted an integral approach connected both sectors by a variety of activities targeting different audiences, and primary care professionals fulfilled mostly a role in the referral of their patients. The structural imbedding of the CSC according an integral approach seems the most promising in reaching the desired outcomes (Chapter 8). Conclusion CSC’ role is promising for establishing a connection between the primary care and the PA sector. However, to make a success of the connection changes are needed at system and sector level. Further research should focus on CSCs’ impact on stimulating PA among primary care patients, and the development of CSC’ role and the connection between both sectors over time.</p

A search filter for increasing the retrieval of animal studies in Embase

Collecting and analysing all available literature before starting a new animal experiment is important and it is indispensable when writing systematic reviews of animal research. In practice, finding all animal studies relevant to a specific research question turns out to be anything but simple. In order to facilitate this search process, we previously developed a search filter for retrieving animal studies in the most often used biomedical database, PubMed. It is a general requirement for systematic reviews, however, that at least two databases are searched. In this report, we therefore present a similar search filter for a second important database, namely Embase. We show that our filter retrieves more animal studies than (a combination of) the options currently available in Embase. Our search filters for PubMed and Embase therefore represent valuable tools for improving the quality of (systematic) reviews and thereby of new animal experiments

Sleep deprivation in rats: effects on learning and cognitive flexibility

Someren, E.J.W. van [Promotor]Feenstra, M.G.P. [Copromotor