Aqueous Phase Separation:a novel and sustainable approach for membrane preparation

This thesis investigates and demonstrates how polymeric membranes can be prepared using the new and more sustainable aqueous phase separation (APS) approach. Polymeric membranes are used on huge scales for kidney dialysis, wastewater treatment, drinking water production, and as a less energy intensive alternative to conventional industrial separation processes. However, the vast majority of polymeric membranes are produced via an unsustainable and environmentally unfriendly process which uses large amounts of reprotoxic chemicals like N methyl 2 pyrrolidinone (NMP) and dimethylformamide (DMF). Unlike the conventional methods the APS approach uses a water based system using a pH or salinity switch instead of toxic organic solvents to prepare membranes. This allows for a more sustainable membrane production process without the use of reprotoxic solvents. This thesis investigates the single-polyelectrolyte approach, where a responsive polyelectrolyte solution is precipitated by a pH switch. Two different polyelectrolytes are used, poly(4 vinyl pyridine) (P4VP) which is soluble in acids and insoluble in base, and polystyrene-alt-maleic acid (PSaMA) which is soluble at neutral and basic conditions and insoluble in acid. Using a variety of parameters such as polymer concentration, acid type and concentration, salt type and concentration both open microfiltration (MF) and ultrafiltration (UF) membranes as well as dense nanofiltration (NF) membranes are prepared. These membranes can match commercially available membranes with retention in aqueous environments, have high mechanical stability and are resistant to various organic solvents. This demonstrates that the single-polyelectrolyte APS approach can match the versatility of conventional preparation methods. While there still plenty of room for improvement, this thesis marks the beginning of a new method that has the potential to significantly improve the sustainability of the membrane industry

Does Pig Density Matter for the Choice of Control Strategies in Classical Swine Fever Epidemic?

This paper examines the importance of pig population density in the area of an outbreak of CSF for the spread of the disease and the choice of control measures. A sector-level market and trade model and a spatial, stochastic, dynamic epidemiological simulation model for the Netherlands were used. Outbreaks in sparsely and densely populated areas were compared under four different control strategies and with two alternative trade assumptions. Results indicate that the control strategy required by current EU legislation is enough to eradicate an epidemic starting in an area with sparse pig population. By contrast, additional control measures are necessary if the outbreak begins in an area with high pig population density. The economic consequences of using preventive slaughter rather than emergency vaccination as an additional control measure depend strongly on the reactions of trading partners. Reducing the number of animal movements significantly reduces the size and length of epidemics in areas with high pig density.Classical Swine Fever epidemics, pig population density, animal transport, emergency vaccination, preventive slaughter, the Netherlands, Livestock Production/Industries,

Strategies to Control Classical Swine Fever: Cost and Risk Perspectives

The paper examines the importance of pig population density in the area of an outbreak of CSF for the spread of the disease and the choice of control measures. A sector-level market and trade model and a spatial, stochastic, dynamic epidemiological simulation model for the Netherlands were used. Outbreaks in sparsely and densely populated areas were compared under four different control strategies and with two alternative trade assumptions. Results indicate that the control strategy required by current EU legislation is enough to eradicate an epidemic starting in an area with sparse pig population. By contrast, additional control measures are necessary if the outbreak begins in an area with high pig population density. The economic consequences of using preventive slaughter rather than emergency vaccination as an additional control measure depend strongly on the reactions of trading partners. Reducing the number of animal movements significantly reduces the size and length of epidemics in areas with high pig density.Classical Swine Fever epidemics, pig population density, animal transport, emergency vaccination, preventive slaughter, the Netherlands, Farm Management,

Reduction of Coxiella burnetii prevalence by vaccination of goats and sheep, the Netherlands

Recently, the number of human Q fever cases in the Netherlands increased dramatically. In response to this increase, dairy goats and dairy sheep were vaccinated against Coxiella burnetii. All pregnant dairy goats and dairy sheep in herds positive for Q fever were culled. We identified the effect of vaccination on bacterial shedding by small ruminants. On the day of culling, samples of uterine fluid, vaginal mucus, and milk were obtained from 957 pregnant animals in 13 herds. Prevalence and bacterial load were reduced in vaccinated animals compared with unvaccinated animals. These effects were most pronounced in animals during their first pregnancy. Results indicate that vaccination may reduce bacterial load in the environment and human exposure to C. burnetii

Caudal cervical vertebral morphological variation is not associated with clinical signs in Warmblood horses

Background Variation in equine caudal cervical spine morphology at C6 and C7 has high prevalence in Warmblood horses and is suspected to be associated with pain in a large mixed-breed group of horses. At present no data exist on the relationship between radiographic phenotype and clinical presentation in Warmblood horses in a case-control study. Objectives To establish the frequency of radiographically visible morphologic variation in a large group of Warmblood horses with clinical signs and compare this with a group without clinical signs. We hypothesised that occurrence of morphologic variation in the case group would not differ from the control group, indicating there is no association between clinical signs and morphologic variation. Study design Retrospective case-control. Methods Radiographic presence or absence of morphologic variation of cervical vertebrae C6 and C7 was recorded in case (n = 245) and control horses (n = 132). Case and control groups were compared by univariable Pearson's Chi-square and multivariable logistic regression for measurement variables age, sex, breed, degenerative joint disease and morphologic variation at C6 and C7. Odds ratio and confidence intervals were obtained. A P <= 0.05 was considered statistically significant. Results Morphologic variation at C6 and C7 (n = 108/377 = 28.6%; Cases 58/245 = 23.7%; Control 50/132 = 38%) was less frequent in horses with clinical signs in univariable testing (OR 0.48, 95% CI 0.3-0.8, P = 0.001). Age, sex, breed and degenerative joint disease were not retained in the final multivariable logistic regression step whereas morphologic variation remained significantly less present in horses with clinical signs. Main limitations Possible demographic differences between equine clinics. Conclusions Morphologic variation in the caudal cervical spine was detected more frequently in horses without clinical signs. Therefore, radiographic presence of such variation does not necessarily implicate the presence of clinical signs