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Sample for the Dutch FADN 2017
No full textThe FADN (Farm Accountancy Data Network) is a European instrument for evaluating the income of agricultural holdings and the impacts of the Common Agricultural Policy. The farms included in the Dutch FADN are a sample of agricultural and horticultural companies from the Agricultural Census. This report explains the background of the sample and the developments concerning the population and sample of 2017. All phases - from the determination of the selection plan, the recruitment of farms to the quality control of the final sample - are described in this report
Comparing thermal inactivation to a combined process of moderate heat and high pressure : Effect on ascospores in strawberry puree
No full textHigh pressure processing is a mild preservation process that inactivates pathogenic and spoilage micro-organisms in food products, but preserves the fresh characteristics of a product. Compared to untreated product, an enhanced shelf life is obtained during refrigerated storage. Knowledge on the use of high pressure pasteurisation aimed for ambient storage is limited. The aim of this research was to investigate if a combination of high pressure and moderate heat could be used to produce a shelf-stable high-acid fruit product. Ascospores of the heat resistant fungi Talaromyces macrosporus and Aspergillus fischeri were added to fresh strawberry puree that served as a model system. The effect of the processing steps and storage at ambient temperature for 2 weeks was studied on viability of the ascospores. A preheating step at 69 °C/2 min resulted in full or partial activation of A. fischeri and T. macrosporus spores, respectively. The pressure build-up by the process without any holding time resulted in additional activation of spores. A combination of moderate heat (maximum 85–90 °C) and high pressure (500–700 MPa) for holding times up to 13 min inactivated these highly resistant spores much faster than a heat treatment alone. At Tmax = 85 °C and 600 MPa the spores of T. macrosporus and A. fischeri were inactivated by 5.0 and 5.5 log10 after 13 and 7 min, respectively. At Tmax = 85 °C the heat treatment alone did not reduce the viability of these spores up to 60 min of treatment. At Tmax = 90 °C the holding time of the combined pressure-heat treatment could be reduced to obtain the same degree of inactivation of the heat resistant fungi. In addition, treated and untreated ascospores in strawberry puree were stored for 14 days at room temperature to evaluate delayed outgrowth of spores. Untreated ascospores of A. fischeri were activated by storage in the puree. However, at conditions combining high pressure ≥ 600 MPa with Tmax ≥ 85 °C for 13 min, heat resistant fungi were successfully inactivated. This research showed that a combination of moderate heat and pressure can drastically improve the effectiveness to inactivate heat-resistant ascospores in a high-acid fruit product compared to a heat treatment, potentially resulting in a better product quality.</p
Environmental risk assessment of pesticides currently applied in Ghana
No full textRegistration of pesticides for use in Ghana is based on prospective environmental risk assessment (ERA) to assess the risks of future pesticide use on the environment. The present study evaluated whether pesticides currently used by Ghanaian farmers may harm the aquatic and terrestrial environment under day-to-day farm practice by performing a 1st tier ERA for terrestrial and aquatic environment and a 2nd tier ERA for the aquatic environment using existing scenarios and models. Results of the 1st tier risk assessment indicated that in the investigated regions in south Ghana, many pesticides might pose an acute risk to aquatic ecosystems adjacent to the treated fields while lambda cyhalothrin, chlorpyrifos, cypermethrin, dimethoate, mancozeb, carbendazim, sulphur, maneb and copper hydroxide may pose the highest chronic risks. Butachlor, dimethoate and carbendazim may pose acute risks to the terrestrial soil ecosystem, while glyphosate, chlorpyrifos, imidacloprid, dimethoate, mancozeb, carbendazim, maneb, copper hydroxide and cuprous oxide may pose the highest chronic risks. Many insecticides and some fungicides may pose acute risks to bees and terrestrial non-target arthropods. The 2nd tier acute aquatic risk assessment showed that most risks were substantiated using species sensitivity distribution (SSD). Actual pesticide use was a factor of 1.3–13 times higher than the recommended label instructions, indicating a general practice of overdosing. The case study shows that the PRIMET model in combination with the SSD concept may offer pesticide registration authorities in Ghana a means to assess environmental risks associated with pesticide usage in a user-friendly and cost-effective manner.</p
Impact of transformation, photodegradation and interaction with glutaraldehyde on the acute toxicity of the biocide DBNPA in cooling tower water
No full textThe reuse of cooling tower water (CTW) can substantially lower the freshwater footprint of cooling towers. CTW requires desalination before its reuse, and pre-treatment before desalination enhances the desalination efficiency. Constructed wetlands (CWs) have been shown to remove fractions from CTW that hamper physico-chemical desalination technologies, and thus provide adequate pre-treatment. However, CTW contains biocides, and these and their transformation products are potentially toxic to aquatic fauna in surface flow CWs. Therefore, we assessed the acute toxicity to daphnids of CTW which contained the biocide 2,2-dibromo-3-nitrilopropionamide (DBNPA), and the impact of photodegradation and the presence of biocide glutaraldehyde on its toxicity. It was observed that the toxicity of DBNPA in CTW was lower than that reported in the literature, and non-target screening showed that this was due to rapid DBNPA transformation, via 2-monobromo-3-nitrilopropionamide (MBNPA) and nitrilopropionamide (NPA). Photodegradation resulted in an increased CTW toxicity after 1 h of illumination as a result of the formation of new DBNPA transformation products, and subsequent decrease in toxicity after 48 h. The simultaneous presence of DBNPA and glutaraldehyde resulted in the formation of interaction products. Photodegradation did not result in unique interaction products, but increased the rate of interaction product formation, leading to a decrease in toxicity. Due to the toxicity of DBNPA in CTW and the effect of photodegradation on this toxicity, it is not recommended to use a surface flow CW as first treatment step in a multistage CW-system for the treatment of CTW.</p
Validation of an antimicrobial susceptibility testing protocol for Brachyspira hyodysenteriae and Brachyspira pilosicoli in an international ring trial
No full textBrachyspira hyodysenteriae and Brachyspira pilosicoli cause economically important enteric disease in pigs. Treatment of these infections often includes antimicrobial administration, which can be most effective when therapeutic options are informed by antimicrobial susceptibility testing data. Here we describe a method for broth dilution antimicrobial susceptibility testing of these bacteria, both of which are difficult to culture in vitro. The protocol was evaluated for its fitness for use in an inter-laboratory ring trial involving eight laboratories from seven countries, and employing eleven test strains (5 Brachyspira hyodysenteriae including the type strain B78T and 6 Brachyspira pilosicoli) and six antibiotics. Overall intra- and inter-laboratory reproducibility of this method was very good (>90 % MICs at mode +/- 1 log2). Whole genome sequencing revealed good correspondence between reduced susceptibility and the presence of previously defined antimicrobial resistance determinants. Interestingly, lnu(C) was identified in B. pilosicoli isolates with elevated MICs of lincomycin, whilst tva(B) was associated with elevated MICs of pleuromutilins in this species. We designated two new control strains with MICs lying within currently tested ranges, including for the pleuromutilins, in contrast to the control strain B. hyodysenteriae B78T. These were deposited at the DSMZ-German Collection of Microorganisms and Cell Cultures GmbH. The validation of a standard protocol and identification of new control strains facilitates comparisons between studies, establishment of robust interpretative criteria, and ultimately contributes to rational antimicrobial use when treating infected livestock.</p
An efficient procedure to assist in the re-parametrization of structurally unidentifiable models
No full textAn efficient method that assists in the re-parametrization of structurally unidentifiable models is introduced. It significantly reduces computational demand by combining numerical and symbolic identifiability calculations. This hybrid approach facilitates the re-parametrization of large unidentifiable ordinary differential equation models, including models where state transformations are required. A model is first assessed numerically, to discover potential structurally unidentifiable parameters. We then use symbolic calculations to confirm the numerical results, after which we describe the algebraic relationships between the unidentifiable parameters. Finally, the unidentifiable parameters are substituted with new parameters and simplification ensures that all the unidentifiable parameters are eliminated from the original model structure. The novelty of this method is its utilisation of numerical results, which notably reduces the number of symbolic calculations required. We illustrate our procedure and the detailed re-parametrization process in 5 examples: (1) an immunological model, (2) a microbial growth model, (3) a lung cancer model, (4) a JAK/STAT model, and (5) a small linear model with a non-scalable re-parametrization.</p
Nutrition and health of edible insects
No full textPURPOSE OF REVIEW: Elucidate the effect of insects as feed and food on nutrition and health of humans and animals. RECENT FINDINGS: A new sector is developing of insects as food and feed. The academic interest is growing exponentially. In addition to their high nutritional values, there are also health benefits. These relate to prebiotic effects of insect products, such as chitin on humans and animals. Insects have a large reservoir of antimicrobial peptides. Some insect species have shown to have antioxidant properties. SUMMARY: The increasing demand for meat and the limited amount of land availability prompt the search for alternative protein sources. Insects require less land and have a lower environmental impact than meat products. In addition to having a high nutritional value, they have also health benefits. Several edible insect species can be grown on organic side streams, in this way contributing to a circular economy. The number of scientific articles increased exponentially, and more than 290 start-ups are now engaging in its production and marketing. Food safety issues are not a major issue but need to be carefully checked when organic waste streams are used. The main strategies related to consumer issues are disguising the insects in familiar products and making them tasty.</p
Higher, better, faster!? : ultra-high field magnetic resonance imaging and spatially resolved spectroscopy
No full textMagnetic Resonance Imaging (MRI) and spatially resolved spectroscopy are valuable Magnetic Resonance (MR) techniques ranging from clinical diagnostics and research to applications in environmental and plant sciences. The key advantage is the ability to non-invasively and non-destructively yield information which other techniques cannot provide. A disadvantage of MR techniques, however, is their relatively low sensitivity, which poses limitations to the minimal spatial resolution and target concentration or comes at the expense of long experiment times. The Signal-to-Noise Ratio (SNR) can generally be increased by increasing the main magnetic field strength B0, increasing the sensitivity of the detector, reducing the noise of the coil or enhancing the signal by hyperpolarisation techniques. In this thesis, we mainly focussed on SNR increase by increasing the B0 (cf. chapters 2-6) and to a certain extent by increasing the detector sensitivity (cf. chapters 2,3 and 5), as well as the enhancement by chemical shift saturation transfer (cf. chapter 6). Ultra-high magnetic field strength for MRI and spatially resolved spectroscopy are anticipated by the research community both with excitement as well as with precaution. Opportunities in terms of increase of both SNR and spectral resolution meet the challenges concerning susceptibility artefacts which cause image distortions and line broadening. During the research project leading to this thesis, we have identified both opportunities as well as challenges on phantoms and biological specimen. In chapter 1, the main milestones in the discovery of the fundamental physical phenomenon of nuclear magnetic resonance (NMR) and MRI techniques, as well as the road towards the different applications, are explained. The basics of MRI and spatially resolved spectroscopy are discussed, including MR image formation and the most commonly used sequences. The research field of Magnetic Resonance Microscopy (MRM) is set into context, and main hardware differences between the different research areas of MRI, i.e. clinical, preclinical and microimaging, are highlighted. The limitations to MR techniques, being the low SNR, and opportunities to increase the SNR are discussed. In terms of additional benefits and challenges at ultra-high field, susceptibility mismatches which represent a significant challenge in high field MRI are highlighted. A short introduction to spatially resolved spectroscopy methods is given. In chapter 2, the SNR-increase was quantified systematically across different high-field microimaging systems. In chapter 3, we describe a method protocol for using the uNMR-nl ultra-high field spectrometer (22.3 T) and calibrate new or home-built microcoils. Sample preparation for using solenoid coils is described, and adjustments for MRI experiments are described. A case study for samples posing challenges to ultra-high field MRI due to susceptibility problems is shown in chapter 4. In chapter 5, magnetic resonance imaging and spatially resolved spectroscopy were combined to evaluate the potential of ultra-high field MRI for plant sciences. While the ultra-high magnetic field is suitable for spatially resolved spectroscopy due to the increased SNR improving the detection limit, chemical exchange saturation transfer (CEST) imaging can further improve the detection limit significantly for a number of metabolites which contain exchangeable protons. In chapter 6, we investigated the additional advantage of CEST at ultra-high field, namely the increase of the selectivity towards the desired metabolite on 7.0 T, 17.2 T and 22.3 T systems. In the general discussion (Chapter 7), we summarise the main findings and conclusions of this thesis. The lessons from ultra-high field MRI and spatially resolved spectroscopy are discussed from a hardware and experimental point of view. We highlight that both the main magnetic field strength and other hardware components, such as gradient strength and detector sensitivity, are important. Experimental considerations, which in particular have to be taken into account when working at ultra-high-field strengths are the chemical shift displacement when performing localised spectroscopy, strategies to reduce susceptibility effects and sequence optimisation. Other strategies for SNR increase, such as cryoprobes and hyperpolarisation, are briefly discussed for a future outlook. As ultra-high field MRM is a research field which usually comes together with small sample sizes, perspectives for different applications such as clinical research, environmental sciences, wastewater treatment, and plant sciences are discussed. Finally, this chapter concludes with an outlook for ultra-high field MRI and spatially resolved spectroscopy for magnetic field strengths beyond 22.3 T. Overall, we conclude that ultra-high field MRI and spatially resolved spectroscopy are highly beneficial as it leads to higher spatial resolutions, faster acquisition times and improved detection limits for metabolites. These advantages can be in the future further extended to a variety of applications. Novel acquisition approaches, hardware and sample preparation, can be additionally optimised for each application to benefit maximally from the state-of-the-art 22.3 T system
Studying the role of estrogen receptor alpha in the developmental toxicity of diethylstilbestrol using alternative testing strategies
No full textDiethylstilbestrol (DES) is a synthetic estrogen that has been used between the 1940s and 1970s by pregnant women to prevent miscarriages and premature delivery by stimulating the synthesis of estrogen and progesterone in the placenta. However, use of DES appeared to cause a wide range of adverse effects, such as clear cell vaginal adenocarcinoma in the daughters of women who took the drug, and developmental and reproductive toxicity. These adverse effects have often been attributed to the functional estrogen receptor alpha (ERα), since it has been reported that ERα is needed to induce DES-mediated adverse developmental and reproductive effects in neonates. The question has been raised why DES behaves differently from the endogenous ERα agonist 17β-estradiol (E2), even though the molecular dimensions and binding orientations of DES and E2 to the ERα are almost identical. The research described in this thesis aimed to investigate the possible differences in the estrogenicity and developmental toxicity between DES and E2, using different in vitro and in silico approaches, focussing on the potential role of possible differences in ERα-mediated effects in the underlying mode of action. Accordingly, first the effect of DES and E2 on ERα-mediated reporter gene expression, ERα-mediated T47D breast cancer cell proliferation, and ERα-coregulator interactions and gene expression in T47D cells were evaluated. In addition, the effects of DES and E2 in two alternative developmental toxicity assays (the ES-D3 cell differentiation assay of the embryonic stem cell test (EST) and the zebrafish embyotoxicity test (ZET)) and the potential role of ERα in these effects were evaluated. Finally, possible dose-dependent differences in internal dose levels of DES and E2 were evaluated with help of PBK modelling, in order to elucidate to what extent possible differences in kinetics could play a role in differential in vivo effects of DES and E2. Altogether, the data show that two estrogens E2 and DES differ in their biological effects related to development in a subtle but significant way. At the cellular level, DES and E2 show high similarities in the molecular pathways that relate to ERα-mediated effects with small significant differences that may contribute to the developmental toxicity in part via potential epigenetic effects of DES. The in vitro developmental toxicity assays EST and ZET can discriminate DES from E2 in terms of developmental toxicity, but at the same time do not capture the full mode of action underlying DES-induced developmental toxicity. Finally, it was shown that in addition to the subtle differences in toxicodynamics, substantial differences in internal concentrations (endogenous E2 concentrations compared to predicted DES concentrations in women that took DES as medication), add to the differential in vivo effects of E2 and DES
