Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    High levels of contact dermatitis and decreased mobility in broiler breeders, but neither have a relationship with floor eggs
    Oever, Anna C.M. van den; Bolhuis, Liesbeth ; Ven, Lotte J.F. van de; Kemp, Bas ; Rodenburg, Bas - \ 2020
    Poultry Science 99 (2020)7. - ISSN 0032-5791 - p. 3355 - 3362.
    broiler breeder - floor egg - foot pad dermatitis - genetic line - leg health

    Contact dermatitis, both on the foot pads and hocks, is a well-known health issue in broilers. Less is known about contact dermatitis in broiler breeders, however, although they have many risk factors for developing leg health problems in common with broilers. This study aimed to describe the prevalence and severity of contact dermatitis during the production cycle in 5 lines of broiler breeders, investigate possible causes of contact dermatitis, and study its relationship with gait, egg production, and floor egg percentage. Five commercially available genetic lines of broiler breeders were housed in 21 pens of 550 females and 50 males from 20 to 60 wk of age. Every 10 wk litter quality, leg health measurements (foot pad dermatitis, hock burn, and gait) and body weight were assessed of 50 random hens per pen. Total number of eggs, number of eggs laid outside the nest (floor eggs), and mortality were recorded daily per pen. Prevalence of foot pad dermatitis, hock burn, and gait problems increased with age. Litter quality started to decrease at 50 wk of age. Prevalence of foot pad dermatitis was affected by litter quality, whereas genetic line had little effect. One genetic line was more prone to developing hock burns, though generally the prevalence of hock burn (13%) was much lower than that of foot pad dermatitis (74%). The percentage of broiler breeders with gait problems increased up to 24% with age, but this was not related to the prevalence of contact dermatitis. The lines differed in body weight from 32 wk of age onwards, and a higher body weight was related to lower egg production and higher cumulative mortality. The percentage of floor eggs was not related to leg health parameters or genetic line. Broiler breeders thus have similar leg health problems as broilers, but these problems are not related to the percentage of floor eggs, suggesting that other factors are involved in the undesirable behavior of floor laying.

    Parallel genetic origin of foot feathering in birds
    Bortoluzzi, Chiara ; Megens, Hendrik-Jan ; Bosse, Mirte ; Derks, Martijn ; Dibbits, Bert ; Laport, Kimberley ; Weigend, Steffen ; Groenen, Martien ; Crooijmans, Richard - \ 2020
    Wageningen University
    PRJEB36674 - ERP119891 - chicken - parallel evolution - foot feathering - Gallus gallus
    Understanding the genetic basis of similar phenotypes shared between lineages is a long-lasting research interest. Even though animal evolution offers many examples of parallelism, for many phenotypes little is known about the underlying genes and mutations. We here use a combination of whole-genome sequencing, expression analyses, and comparative genomics to study the parallel genetic origin of ptilopody (Pti) in chicken. Ptilopody (or foot feathering) is a polygenic trait that can be observed in domesticated and wild avian species and is characterized by the partial or complete development of feathers on the ankle and feet. In domesticated birds, ptilopody is easily selected to fixation, though extensive variation in the type and level of feather development is often observed. By mean of a genome-wide association analysis, we identified two genomic regions associated with ptilopody. At one of the loci, we identified a 17 kb deletion affecting PITX1 expression, a gene known to encode a transcription regulator of hindlimb identity and development. Similarly to pigeon, at the second loci we observed ectopic expression of TBX5, a gene involved in forelimb identity and a key determinant of foot feather development. We also observed that the trait evolved only once as foot feathered birds share the same haplotype upstream TBX5. Our findings indicate that in chicken and pigeon ptilopody is determined by the same set of genes that affect similar molecular pathways. Our study confirms that ptilopody has evolved through parallel evolution in chicken and pigeon.
    Parallel Genetic Origin of Foot Feathering in Birds
    Bortoluzzi, Chiara ; Megens, Hendrik-Jan ; Bosse, Mirte ; Derks, Martijn F.L. ; Dibbits, Bert ; Laport, Kimberly ; Weigend, Steffen ; Groenen, Martien A.M. ; Crooijmans, Richard P.M.A. - \ 2020
    Molecular Biology and Evolution (2020). - ISSN 0737-4038
    Understanding the genetic basis of similar phenotypes shared between lineages is a long-lasting research interest. Even though animal evolution offers many examples of parallelism, for many phenotypes little is known about the underlying genes and mutations. We here use a combination of whole-genome sequencing, expression analyses, and comparative genomics to study the parallel genetic origin of ptilopody (Pti) in chicken. Ptilopody (or foot feathering) is a polygenic trait that can be observed in domesticated and wild avian species and is characterized by the partial or complete development of feathers on the ankle and feet. In domesticated birds, ptilopody is easily selected to fixation, though extensive variation in the type and level of feather development is often observed. By means of a genome-wide association analysis, we identified two genomic regions associated with ptilopody. At one of the loci, we identified a 17-kb deletion affecting PITX1 expression, a gene known to encode a transcription regulator of hindlimb identity and development. Similarly to pigeon, at the second loci, we observed ectopic expression of TBX5, a gene involved in forelimb identity and a key determinant of foot feather development. We also observed that the trait evolved only once as foot-feathered birds share the same haplotype upstream TBX5. Our findings indicate that in chicken and pigeon ptilopody is determined by the same set of genes that affect similar molecular pathways. Our study confirms that ptilopody has evolved through parallel evolution in chicken and pigeon.
    Green Challenges: plant en bodemweerbaarheidtegen ondergrondse ziekten
    Streminska, Marta ; Breeuwsma, Suzanne ; Huisman, Huei Ming ; Vos, Ric de; Eekelen, Henriette van; Stevens, Luc ; Salm, Caroline van der - \ 2020
    Bleiswijk : Stichting Wageningen Research, Wageningen Plant Research, Business unit Glastuinbouw (Rapport WPR 943) - 61
    Crops in soil-based and soilless greenhouse cultivation systems are susceptible to various soilborne diseases, such as foot and root rot and wilting, caused by pathogens as Fusarium and Pythium. The Grºeen Challenges project aims to reduce the use of chemical plant protection products and to develop new measures and strategies for disease and pest control through a system approach. This project investigated which measures can be taken to promote soil disease suppression and induced plant resistance against soilborne pathogens (Fusarium and Pythium) in different horticultural crops: vegetable crops (tomato and cucumber) and ornamental crop (lisianthus).
    The long road to lameness: considering walking distance as a challenge in pasture-based dairy production
    Crossley, R.E. ; Conneely, Muireann ; Browne, Natasha ; Sugrue, Katie ; Boer, I.J.M. de; Bokkers, Eddie - \ 2020
    In: WIAS Annual Conference 2020. - WIAS - p. 81 - 81.
    One challenge of pasture-based dairy production systems is that grazing cattle must walk greater distances from the paddock to the parlour to facilitate milking. In Ireland, cows spend an average of 241 days per year at grass, typically brought to the parlour for milking twice per day, resulting in a relatively large portion of their daily time budget spent walking.Longer walking distances, however, may be associated with increased lameness, thus impacting their welfare. To investigate the potential impact of walking distance on lameness and welfare, the first step is establishing a better picture of the typical distances covered by grazing dairy cattle in Ireland. During the grazing season (April-September 2019) 100 farms were visited throughout the primary dairy producing counties of Ireland. Farmers were surveyed regarding their grazing practices and their cows were mobility scored by trained observers using a 4-point scoring system (0 = good, 1 = imperfect, 2 = impaired, 3 = severely impaired mobility). Farms had a mean size of 45.2ha (range= 14-101ha), milking an average of 124 cows (range = 38-253) twice daily. According to farmers’ responses, the average walking distance between the parlour and the furthest grazing paddock had a mean of989m (range = 400-2000m). Cows could be travelling this path 4 times per day, thus cows walk on average up to 4.0km/d. On 51% of farms, cows were collected from paddocks on foot, while 31% of farmers used some type of motorised vehicle. Using vehicles to move cattle has been associated with increased hoof injuries as hurried animals have difficulty avoiding hazards on roadway surfaces, however, this was not reflected in the data from this survey. Mobility scoring indicated that the mean proportion of cows across farms with score 0 was 36% (range = 9-76%), score 1 was 54% (range = 22-76%), score 2 was 9% (range= 1-27%), and score 3 was 1% (range = 0-5%). A relatively low level of cows scored 2/3,however, a high proportion of cows scored 1 which may reflect other underlying issues,such as roadway conditions, another key factor associated with lameness. While this survey illustrates the potential stress imposed on grazing dairy cattle through long walking distances,further study is required to investigate possible associations with lameness and welfare.
    The Impacts of Suboptimal Mobility in Pasture-based Dairy Systems
    O'Connor, A. ; Bokkers, Eddie ; Boer, I.J.M. de; Hogeveen, H. ; Sayers, R. ; Byrne, N. ; Ruelle, E. ; Shalloo, L. - \ 2020
    In: WIAS Annual Conference 2020. - WIAS - p. 30 - 30.
    Suboptimal mobility refers to any abnormality to a cow’s gait which causes a deviation from the optimal walking pattern of a cow. Suboptimal mobility is an area of concern from an economic, environmental and animal welfare point of view. While the potentialrisk factors and impacts of suboptimal mobility in non-pasture-based systems are reported on throughout the literature, the same information is lacking for seasonal calving, pasture-based systems. The overall aim of this project was to determine the impacts of suboptimal mobility in a pasture-based dairy system. To achieve this we determined 1) the association between claw disorders and suboptimal mobility; 2) the cow and herd-level risk factors associated with suboptimal mobility; 3) the production and reproductive impacts associated with suboptimal mobility; 4) the economic and environmental consequences of suboptimal mobility. Data from 11,116 cows from 68 Irish pasture-based dairy herds were collected. Cows were mobility scored and body condition scored (BCS). Production data(milk, fat, and protein yields, and somatic cell count), reproductive data (calving dates,calving interval, and culling), and other cow-level data (breed type, and genetic transmitting abilities for health and production traits) were available for each cow. Herd-level data including cow path quality and maintenance practices, distances cows walk to and from pasture each day, and foot bathing regimes on farm were collected for each herd via an online survey completed by the herd owners. Our study showed that all severities of claw disorders (ranging from mild to severe), are associated with specific mobility scores. Furthermore,cows with higher yields, elevated SCC, less body condition, and cows with a genetic predisposition for lameness are all potential risk factors for suboptimal mobility. We also found that certain cow breeds such as Jersey type cows are associated with a reduced risk for having suboptimal mobility. At the herd-level, both the quality of cow paths and the distance cows must walk each day are associated with an increased proportion of suboptimal mobility. Finally, herds with higher proportions of suboptimal mobility have lower economic returns and higher total costs. These herds are also associated with increased greenhouse gas emissions per kg of fat and protein corrected milk yield.
    The Impacts of Suboptimal Mobility in Pasture-based Dairy Systems
    O'Connor, Aisling ; Bokkers, E.A.M. ; Boer, Imke de; Hogeveen, Henk ; Sayers, R. ; Byrne, N. ; Ruelle, E. ; Shalloo, L. - \ 2020
    Suboptimal mobility refers to any abnormality to a cow’s gait which causes a deviation
    from the optimal walking pattern of a cow. Suboptimal mobility is an area of concern
    from an economic, environmental and animal welfare point of view. While the potential
    risk factors and impacts of suboptimal mobility in non-pasture-based systems are reported
    on throughout the literature, the same information is lacking for seasonal calving, pasture-
    based systems. The overall aim of this project was to determine the impacts of suboptimal
    mobility in a pasture-based dairy system. To achieve this we determined 1) the
    association between claw disorders and suboptimal mobility; 2) the cow and herd-level risk
    factors associated with suboptimal mobility; 3) the production and reproductive impacts
    associated with suboptimal mobility; 4) the economic and environmental consequences
    of suboptimal mobility. Data from 11,116 cows from 68 Irish pasture-based dairy herds were
    collected. Cows were mobility scored and body condition scored (BCS). Production data
    (milk, fat, and protein yields, and somatic cell count), reproductive data (calving dates,
    calving interval, and culling), and other cow-level data (breed type, and genetic transmitting
    abilities for health and production traits) were available for each cow. Herd-level data
    including cow path quality and maintenance practices, distances cows walk to and from
    pasture each day, and foot bathing regimes on farm were collected for each herd via an
    online survey completed by the herd owners. Our study showed that all severities of claw
    disorders (ranging from mild to severe), are associated with specific mobility scores. Furthermore,
    cows with higher yields, elevated SCC, less body condition, and cows with a genetic
    predisposition for lameness are all potential risk factors for suboptimal mobility. We also
    found that certain cow breeds such as Jersey type cows are associated with a reduced
    risk for having suboptimal mobility. At the herd-level, both the quality of cow paths and the
    distance cows must walk each day are associated with an increased proportion of suboptimal
    mobility. Finally, herds with higher proportions of suboptimal mobility have lower economic
    returns and higher total costs. These herds are also associated with increased green house
    gas emissions per kg of fat and protein corrected milk yield.
    Emergency foot-and-mouth disease vaccines a Malaysia 97 and A22 Iraq 64 offer good protection against heterologous challenge with a variant serotype a ASIA/G-IX/SEA-97 lineage virus
    Nagendrakumar, B. ; Dekker, Aldo ; Eblé, Phaedra L. ; Hemert-Kluitenberg, Froukje van; Weerdmeester, Klaas ; Horsington, Jacquelyn ; Wilna, Vosloo W. - \ 2020
    Vaccines 8 (2020)1. - ISSN 2076-393X
    Cross-protection - FMD - Foot-and-mouth disease virus - Heterologous protection - Vaccine - Vaccine efficacy

    The continuous emergence of foot-and-mouth disease virus (FMDV) serotype A variants in South East Asia is of concern for international FMDV antigen banks, especially when in vitro tests predict a low antigenic match. A vaccination-challenge study was performed by using two emergency FMDV vaccines with A22 Iraq 64 (A22 IRQ) and A Malaysia 97 (A MAY 97) strains, against challenge with a variant strain of FMDV A/Asia/G-IX/SEA-97 lineage at 7- and 21-day post-vaccination (dpv). At 7 dpv, three of five female calves vaccinated with A MAY 97 and four of five vaccinated with A22 IRQ did not show lesions on the feet and were considered protected, while at 21 dpv all five calves were protected with each vaccine, indicating equal efficacy of both vaccine strains. Calves were protected despite relatively low heterologous neutralizing antibody titers to the challenge virus at the time of challenge. All the calves developed antibodies to the non-structural proteins, most likely due to the direct intradermolingual (IDL) inoculation. Only one calf from the A MAY 97-7 group had infectious virus in the serum 1–3-day post-challenge (dpc), while no virus could be isolated from the serum of cattle challenged on 21 dpv. The virus could be isolated from the oral swabs of all calves, 1–7 dpc with viral RNA detected 1–10 dpc. Nasal swabs were positive for virus 1–6 dpc in a small number of calves. The time between vaccination and infection did not have an impact on the number of animals with persistent infection, with almost all the animals showing viral RNA in their oro-pharyngeal fluid (probang) samples up to 35 dpc. Despite the poor in vitro matching data and field reports of vaccine failures, this study suggests that these vaccine strains should be effective against this new A/Asia/G/SEA-97 variant, provided they are formulated with a high antigen dose.

    Cross-protection induced by a A/MAY/97 emergency vaccine against intra-serotype heterologous challenge with a foot-and-mouth disease virus from the A/ASIA/G-VII lineage
    Dekker, Aldo ; Sanz-Bernardo, Beatriz ; Singanallur, Nagendrakumar Balasubramanian ; Ludi, Anna B. ; Horsington, Jacquelyn ; Eblé, Phaedra L. ; King, Donald P. ; Vosloo, Wilna - \ 2020
    Vaccines 8 (2020)1. - ISSN 2076-393X
    Cross-protection - FMD - Foot-and-mouth disease - Heterologous protection - Potency test - Vaccine

    Since 2015, outbreaks of foot-and-mouth disease (FMD) in the Middle East have been caused by a new emerging viral lineage, A/ASIA/G-VII. Invitro vaccine matching data indicated that this virus poorly matched (low r1-value) with vaccines that were being used in the region as well as most other commercially available vaccines. The aim of this study was to assess the performance of two candidate vaccines against challenge with a representative field virus from the A/ASIA/G-VII lineage. The results from an initial full dose protection study provided encouraging data for the A/MAY/97 vaccine, while the A22 /IRQ/64 vaccine only protected 2/7 vaccinated animals. In view of these promising results, this vaccine was tested in a potency test (PD50) experiment in which 5 cattle were vaccinated with a full dose, 5 cattle with a 1/3 dose and 5 cattle with a 1/9 dose of vaccine. At 21 days post vaccination these vaccinated cattle and 3 control cattle were challenged intradermolingually with a field isolate from the A/ASIA/G-VII lineage. The intra-serotype heterologous potency test resulted in an intra-serotype heterologous potency of 6.5 PD50 /dose. These data support previous studies showing that a high potency emergency vaccine can protect against clinical disease when challenged with a heterologous strain of the same serotype, indicating that not only the r1-value of the vaccine, but also the homologous potency of a vaccine should be taken into account when advising vaccines to control an outbreak.

    How the neurotoxin β-N-Methylamino-L-Alanine accumulates in bivalves: distribution of the different accumulation fractions among organs
    Lepoutre, Alexandra ; Faassen, E.J. ; Zweers, A.J. ; Lurling, M.F.L.L.W. ; Geffard, Alain ; Lance, E. - \ 2020
    Toxins 12 (2020)2. - ISSN 2072-6651
    The environmental neurotoxin β-methylamino-l-alanine (BMAA) may represent a risk for human health. BMAA accumulates in freshwater and marine organisms consumed by humans. However, few data are available about the kinetics of BMAA accumulation and detoxification in exposed organisms, as well as the organ distribution and the fractions in which BMAA is present in tissues (free, soluble bound or precipitated bound cellular fractions). Here, we exposed the bivalve mussel Dreissena polymorpha to 7.5 µg of dissolved BMAA/mussel/3 days for 21 days, followed by 21 days of depuration in clear water. At 1, 3, 8, 14 and 21 days of exposure and depuration, the hemolymph and organs (digestive gland, the gills, the mantle, the gonad and muscles/foot) were sampled. Total BMAA as well as free BMAA, soluble bound and precipitated bound BMAA were quantified by tandem mass spectrometry. Free and soluble bound BMAA spread throughout all tissues from the first day of exposure to the last day of depuration, without a specific target organ. However, precipitated bound BMAA was detected only in muscles and foot from the last day of exposure to day 8 of depuration, at a lower concentration compared to free and soluble bound BMAA. In soft tissues (digestive gland, gonad, gills, mantle and muscles/foot), BMAA mostly accumulated as a free molecule and in the soluble bound fraction, with variations occurring between the two fractions among tissues and over time. The results suggest that the assessment of bivalve contamination by BMAA may require the quantification of total BMAA in whole individuals when possible.
    Invited review: Compost-bedded pack barns for dairy cows
    Leso, L. ; Barbari, M. ; Lopes, M.A. ; Damasceno, F.A. ; Galama, P. ; Taraba, J.L. ; Kuipers, A. - \ 2020
    Journal of Dairy Science 103 (2020)2. - ISSN 0022-0302 - p. 1072 - 1099.
    animal welfare - compost-bedded pack barn - dairy cow - housing system

    Compost-bedded pack barns (CBP) are receiving increasing attention as a housing system for dairy cows that has potential to improve animal welfare. This article reviews current scientific knowledge about CBP with the aim of providing a comprehensive tool for producers and researchers using this housing system. In CBP, cows are provided with an open bedded pack area rather than the individual stalls and concrete alleys found in freestall systems. The bedded pack, a mixture of organic bedding and cattle excreta, is cultivated frequently (1–3 times per day) to incorporate fresh manure and air into the pack, thus promoting an aerobic composting process. To function well, CBP generally require a large area per cow. Optimal animal densities over the bedded area range from 7.4 to more than 15 m2/cow depending on several factors, including climate, bedding, pack management, and cow characteristics. Studies have indicated that CBP, compared with conventional systems such as freestall barns, have the potential to improve the welfare of dairy cows. In particular, the main reported benefits include improved comfort during resting, better foot and leg health, and more natural animal behavior. Research has also indicated that adequate udder health can be achieved in CBP. However, because the bedded pack has been shown to contain high bacterial concentrations, proper management is essential to maintain adequate cow cleanliness and reduce the risk of mastitis. Controlling pack moisture is consistently indicated as the most important issue with CBP. Especially under cold and humid weather conditions, large amounts of bedding may be necessary to keep the pack adequately dry and comfortable for the cows. Nevertheless, the improvements in cow health may offset the higher costs of bedding.

    Predicting survival in dairy cattle by combining genomic breeding values and phenotypic information
    Heide, E.M.M. van der; Veerkamp, R.F. ; Pelt, M.L. van; Kamphuis, C. ; Ducro, B.J. - \ 2020
    Journal of Dairy Science 103 (2020)1. - ISSN 0022-0302 - p. 556 - 571.
    dairy cow - individual prediction - longevity - survival

    Advances in technology and improved data collection have increased the availability of genomic estimated breeding values (gEBV) and phenotypic information on dairy farms. This information could be used for the prediction of complex traits such as survival, which can in turn be used in replacement heifer management. In this study, we investigated which gEBV and phenotypic variables are of use in the prediction of survival. Survival was defined as survival to second lactation, plus 2 wk, a binary trait. A data set was obtained of 6,847 heifers that were all genotyped at birth. Each heifer had 50 gEBV and up to 62 phenotypic variables that became gradually available over time. Stepwise variable selection on 70% of the data was used to create multiple regression models to predict survival with data available at 5 decision moments: distinct points in the life of a heifer at which new phenotypic information becomes available. The remaining 30% of the data were kept apart to investigate predictive performance of the models on independent data. A combination of gEBV and phenotypic variables always resulted in the model with the highest Akaike information criterion value. The gEBV selected were longevity, feet and leg score, exterior score, udder score, and udder health score. Phenotypic variables on fertility, age at first calving, and milk quantity were important once available. It was impossible to predict individual survival accurately, but the mean predicted probability of survival of the surviving heifers was always higher than the mean predicted probability of the nonsurviving group (difference ranged from 0.014 to 0.028). The model obtained 2.0 to 3.0% more surviving heifers when the highest scoring 50% of heifers were selected compared with randomly selected heifers. Combining phenotypic information and gEBV always resulted in the highest scoring models for the prediction of survival, and especially improved early predictive performance. By selecting the heifers with the highest predicted probability of survival, increased survival could be realized at the population level in practice.

    Quantifying soil carbon stocks and humification through spectroscopic methods: A scoping assessment in EMBU-Kenya
    Claessens, L.F.G. ; Segnini, A. ; Posadas, A. - \ 2019
    Journal of Environmental Management 234 (2019). - ISSN 0301-4797 - p. 476 - 483.
    A soil carbon assessment was performed comparing agricultural cropping systems with natural vegetation along a sampling transect spanning different agro-ecologies on the eastern foot slopes of Mount Kenya in Embu county, 125 km from Nairobi, Kenya. The aim was to determine differences in soil carbon stocks and carbon recalcitrance and relate these to soil textural class, altitude, climatic parameters and land use. Soils from main agricultural systems as tea, coffee and maize-based intercropping, as well as from natural vegetation cover were sampled in triplicates, in five layers from 0 to 30 cm in depth and processed for total carbon analysis. The whole soil samples were also analysed using Laser-Induced Fluorescence Spectroscopy (LIFS) to assess carbon humification. Prototype portable equipment intended for future in situ analysis was used in the lab to ascertain the structure of the most recalcitrant and stable carbon present in different agro-ecosystems. In addition, Near Infrared Spectroscopy (NIRS) was tested for the quantitative analysis of soil carbon, showing that it is a reproducible and low-cost method that provided satisfactory results under the processing conditions of the samples. Results showed wide variation in the level and quality of carbon stored in the soils, depending on soil texture, land use, elevation, climate, agricultural practices and land use history. Considering the heterogeneous nature of sampled soils and the performance of NIRS and LIFS, these results can be used as a basis for the development of fully portable systems able to provide rapid, clean and potentially cost-effective relevant information for soil management.
    Soft dendritic microparticles with unusual adhesion and structuring properties
    Roh, Sangchul ; Williams, Austin H. ; Bang, Rachel S. ; Stoyanov, Simeon D. ; Velev, Orlin D. - \ 2019
    Nature Materials 18 (2019). - ISSN 1476-1122 - p. 1315 - 1320.

    The interplay between morphology, excluded volume and adhesivity of particles critically determines the physical properties of numerous soft materials and coatings1–6. Branched particles2 or nanofibres3, nanofibrillated cellulose4 or fumed silica5 can enhance the structure-building abilities of colloids, whose adhesion may also be increased by capillarity or binding agents6. Nonetheless, alternative mechanisms of strong adhesion found in nature involve fibrillar mats with numerous subcontacts (contact splitting)7–11 as seen in the feet of gecko lizards and spider webs12–17. Here, we describe the fabrication of hierarchically structured polymeric microparticles having branched nanofibre coronas with a dendritic morphology. Polymer precipitation in highly turbulent flow results in microparticles with fractal branching and nanofibrillar contact splitting that exhibit gelation at very low volume fractions, strong interparticle adhesion and binding into coatings and non-woven sheets. These soft dendritic particles also have potential advantages for food, personal care or pharmaceutical product formulations.

    Stripping chronopotentiometry at scanned deposition potential (SSCP) : An effective methodology for dynamic speciation analysis of nanoparticulate metal complexes
    Town, Raewyn M. ; Leeuwen, Herman P. van - \ 2019
    Journal of Electroanalytical Chemistry 853 (2019). - ISSN 1572-6657
    Chemical heterogeneity - Dynamic metal speciation - Humic substances - Lability - Nanoparticulate complexants

    The features of stripping chronopotentiometry at scanned deposition potential (SSCP) are reviewed and placed in context with voltammetric and other dynamic speciation techniques. The advantages of SSCP for speciation analysis of nanoparticulate metal complexes are highlighted. Analogous to other electrochemical techniques, the SSCP wave is rich in information: the measurements from the foot to the plateau of the wave access the relevant parts of the stability distribution and the rate constant distributions. The complete depletion regime of SSCP offers particular advantages due to its ability to unambiguously distinguish between various factors that can confound interpretation of data from other electroanalytical methods, including electrochemical irreversibility, kinetically controlled currents, reduced diffusion coefficient of the metal complex species as compared to the free metal ion, and chemical heterogeneity in the intrinsic binding affinity.

    Healing gardens as therapeutic landscapes
    Veen, E.J. ; Doughty, Karolina - \ 2019
    Although survival rates for cancer are improving, survivors suffer an increased risk of chronic illnesses such as cardiovascular disease and depression. In order to prevent patients from developing these diseases, lifestyle guidelines have been developed. Adherence to these guidelines, however, is low and short-lived. Many patients lack the aspiration, capacity or energy to make lifestyle changes. In this paper we explore a communal ‘healing garden’ as a potential alternative to these lifestyle guidelines, exploring whether it may function as a ‘therapeutic landscape’ for cancer survivors, particularly in stimulating physical activity and healthy eating, but also in facilitating social peer support. Our paper discusses a pilot project in the Netherlands, in which five participants gardened together one-and-a-half hours a week, under supervision, in ten square foot gardening containers. Using a series of physical tests and semi-structured interviews with participants (before, during and after the project), we show that physically the gardening experience did not meet expectations. Nevertheless, the gardening activity was highly satisfying for participants, for a variety of reasons (the activity as such, the harvest, the pleasure of manual labour, and mental rest). Participants reported that the gardening group formed a supportive environment. However, they did not agree on whether that is sufficient to consider the gardening activity a form of social peer support. We conclude that even though the project did not have measurable physical results, it can be regarded a therapeutic landscape for its social benefits.
    Risk assessment of exotic disease incursion and spread
    Cabral, M. ; Taylor, R. ; Vos, C.J. de - \ 2019
    EFSA Journal 17 (2019)S2. - ISSN 1831-4732
    generic model - Import risk assessment - introduction risk - livestock disease - validation

    This Technical Report describes the activities developed in the scope of the EU-FORA Fellowship, within the work programme of risk assessment (RA) of exotic disease incursion and spread, developed at Wageningen Bioveterinary Research (WBVR). The programme focused on the work carried out in the Generic risk assessment for introduction of animal diseases (G-RAID) project, which brings together a number of different generic RA tools from multiple European partners. The aim of the fellowship was to gain understanding of veterinary import risk assessment by using different RA tools and to learn how different algorithms can be used to calculate disease incursion risks. G-RAID's tools cover a wide range of RA methodologies; from purely qualitative, to semi-quantitative and fully stochastic quantitative methods, which allowed the fellow to understand a variety of algorithms used to produce the final risk estimate. The fellowship programme provided the fellow with the chance to learn in detail about how generic RAs are performed across Europe, understanding how to deal with the uncertainty and variability involved in RAs and the potential problems of data availability and reliability. The fellow made an inventory of publicly available databases on disease occurrence and international trade that could be used for import RA and assessed their quality and usefulness for the different generic RA tools. The programme also provided the fellow the opportunity to perform several import risk assessments using the RA tools of G-RAID. She completed a RA on African swine fever using the MINTRISK model developed by WBVR. Furthermore, she assessed the risk of foot and mouth disease introduction using the Rapid Risk Assessment Tool (RRAT) model developed by WBVR and the COMPARE model developed by the Animal and Plant Health Agency (APHA). To this end, the fellow completed a short-term visit to APHA, enabling her to have additional training in quantitative RA and to expand her professional network in this area.

    Finding out why frogs' feet stick
    Langowski, J.K.A. - \ 2019
    Soil lacquer peel do-it-yourself: Simply capturing beauty
    Stoof, Cathelijne R. ; Candel, Jasper H.J. ; Wal, Laszlo A.G.M. Van Der; Peek, Gert - \ 2019
    SOIL 5 (2019)2. - ISSN 2199-3971 - p. 159 - 175.

    Visualization can greatly benefit understanding of concepts and processes, which in soil science and geology can be done using real-life snapshots of soils and sediments in lacquer peels and glue peels. While it may seem complicated, anyone can make such a soil peel for use in classrooms, public places, homes, and offices for teaching, outreach, decoration, and awareness. Technological development has considerably simplified the making of soil peels, but this methodological innovation has not been described in the literature. Here, we report on a thoroughly tested and simple method for taking peels of sandy soils using readily available tools and materials. Our method follows the main previously published steps of preparing a soil face, impregnating the soil face with a fixation agent in the field, extracting the resulting peel, and mounting it on a wooden panel. Yet instead of using lacquers and thinning agents, we use strong though flexible contact adhesive (glue), which has the major advantage that it no longer requires use and mixing of toxic chemicals in the field or reinforcement of the peel to prevent breaking. Moreover, the preservation potential is much higher than with the old method. This new twist to old methods makes creation of soil peels safer, simpler, and more successful, and thereby a true DIY (do-it-yourself) activity. The resulting increased accessibility of making soil and sediment peels can benefit research, teaching, and science communication and can thereby bring the value and beauty of the ground below our feet to students, schools, policy makers, and the general public.

    Short communication: The effects of regrouping in relation to fresh feed delivery in lactating Holstein cows
    Smid, Anne Marieke C. ; Weary, Daniel M. ; Bokkers, Eddie A.M. ; Keyserlingk, Marina A.G. von - \ 2019
    Journal of Dairy Science 102 (2019)7. - ISSN 0022-0302 - p. 6545 - 6550.
    management - mixing - social stress - welfare

    This study tested whether separating regrouping from the time of fresh feed delivery mitigated the effects of regrouping on cow behavior and milk production. Cows (n = 26) were individually introduced into a stable group of 11 animals/pen fed twice daily. Animals were randomly assigned to early regrouping (at 0300 h, approximately 10.5 h after fresh feed delivery and 3.5 h before the next fresh feed delivery) and late regrouping (between 0630 and 0730 h, coinciding with access to fresh feed). For 3 d, starting immediately after regrouping, video recordings continuously monitored feeding and perching (i.e., standing with the 2 front feet in the lying stall) behavior and displacements at the feed bunk. Data loggers were used to quantify lying time and the number of standing bouts; milk production was automatically recorded at each milking. Daily feeding and lying times and the number of standing bouts per day did not differ between treatments or experimental days. Daily perching time and the number of displacements at the feed bunk did not differ between treatments but decreased with experimental day. Average milk production on d 2 and 3 after regrouping (30.6 ± 1.5 kg/d) was lower than during the 3 d before regrouping (32.3 ± 1.5 kg/d), but we observed no effect of treatment on this decline. We conclude that regrouping at a time not associated with fresh feed delivery does not mitigate the negative effects of regrouping.

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