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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    Combining food-based dietary recommendations using Optifood with zinc-fortified water potentially improves nutrient adequacy among 4- to 6-year-old children in Kisumu West district, Kenya
    Kujinga, Prosper ; Borgonjen-van den Berg, Karin J. ; Superchi, Cecilia ; Hove, Hermine J. ten; Onyango, Elizabeth Opiyo ; Andang'o, Pauline ; Galetti, Valeria ; Zimmerman, Michael B. ; Moretti, Diego ; Brouwer, Inge D. - \ 2018
    Maternal and Child Nutrition 14 (2018)2. - ISSN 1740-8695
    children - diets - Optifood - water - zinc
    Children in developing countries often face multiple micronutrient deficiencies. Introduction of zinc-fortified water can increase zinc intake, but additional recommendations are required to address overall diet nutrient adequacy. We developed and tested food-based recommendations (FBRs) that included zinc-fortified water for children aged between 4 and 6 years from rural Kenya to achieve the best possible nutrient adequacy. Dietary intakes of 60 children aged 4–6 years, from Kisumu West district, Kenya, were assessed using a quantitative multipass 24-hr recall. Linear programming model parameters were derived, including a list of foods consumed, median serving sizes, and distribution of frequency of consumption. By using the Optifood linear programming tool, we developed FBRs for diets including zinc-fortified water. FBRs with nutrient levels achieving ≥70% recommended nutrient intake (RNI) of the World Health Organization/Food and Agriculture Organization of the United Nations RNI for most of the 12 considered nutrients were selected as the final recommendations for the children. With no FBRs and no zinc-fortified water, percent RNI coverage range was between 40% and 76% for zinc, improving to 66–101% after introduction of zinc-fortified water. The final set of FBRs achieved nutrient adequacy for all nutrients except for vitamin A (25% RNI) and folate (68% RNI). Introduction of zinc-fortified water combined with FBRs will likely improve the nutrient adequacy of diets consumed by children in Kenya but needs to be complemented with alternative interventions to ensure dietary adequacy.
    Linking slow dynamics and microscopic connectivity in dense suspensions of charged colloids
    Higler, Ruben ; Krausser, Johannes ; Gucht, Jasper Van Der; Zaccone, Alessio ; Sprakel, Joris - \ 2018
    Soft Matter 14 (2018)5. - ISSN 1744-683X - p. 780 - 788.
    The quest to unravel the nature of the glass transition, where the viscosity of a liquid increases by many orders of magnitude, while its static structure remains largely unaffected, remains unresolved. While various structural and dynamical precursors to vitrification have been identified, a predictive and quantitative description of how subtle changes at the microscopic scale give rise to the steep growth in macroscopic viscosity is missing. It was recently proposed that the presence of long-lived bonded structures within the liquid may provide the long-sought connection between local structure and global dynamics. Here we directly observe and quantify the connectivity dynamics in liquids of charged colloids en route to vitrification using three-dimensional confocal microscopy. We determine the dynamic structure from the real-space van Hove correlation function and from the particle trajectories, providing upper and lower bounds on connectivity dynamics. Based on these data, we extend Dyre's model for the glass transition to account for particle-level structural dynamics; this results in a microscopic expression for the slowing down of relaxations in the liquid that is in quantitative agreement with our experiments. These results indicate how vitrification may be understood as a dynamical connectivity transition with features that are strongly reminiscent of rigidity percolation scenarios.
    Carbon dioxide fluxes in the city centre of Arnhem, A middle-sized Dutch city
    Kleingeld, Eva ; Hove, Bert van; Elbers, Jan ; Jacobs, Cor - \ 2018
    Urban Climate 24 (2018). - ISSN 2212-0955 - p. 994 - 1010.
    Carbon dioxide - Eddy-covariance - Flux variability - Long-term flux measurements - Source partitioning, emission inventory - Urban

    This paper reports on the temporal variability of carbon dioxide fluxes in the city centre of Arnhem, a middle-sized Dutch city. The fluxes were continuously measured during four years (2012-2016) using the eddy-covariance method. Additionally, continuous meteorological measurements were carried out. We also analysed data from 30-minute traffic counts performed during those years. Results indicate that the city centre of Arnhem is a strong emission source of CO2 compared to many other cities. The measured annual CO2 flux equals about 8.0kgCm-2 yr-1. Heterogeneity within the footprint of the EC tower appeared to have no or only a small influence on the estimated annual and seasonal carbon fluxes. Sector analysis shows that CO2 fluxes are consistently higher in sectors with the highest built-up surface fraction. However, no statistically significant relationship could be determined. Traffic and space-heating related burning of natural gas are the main emission sources. Weekly and diurnal variations in CO2 flux are clearly correlated with traffic intensity, whereas seasonal variation can largely be explained by space heating demand. Partitioning of the total flux into a heating-related and traffic-related flux revealed that space heating accounts for up to 60% to the total flux during winter. Traffic intensity remains more or less constant throughout the year. In summer, when space heating is absent, CO2 emission is almost entirely related to traffic intensity. However, our estimations suggest that human respiration could have a non-negligible share in this. The contribution of the small fraction of urban green in the city centre is probably minimal. The annual emissions for the city centre estimated from our EC measurements are 20-25% lower than those reported for the whole city by the official emission inventory. Climate projections for the Netherlands suggest that in 2050 Heating Degree Days would be reduced by 27% resulting into a 32% reduction of the heating-related emission flux, without a change in fossil fuel use.

    Dendrimer-encapsulated nanoparticle-core micelles as a modular strategy for particle-in-a-box-in-a-box nanostructures
    Hove, J.B. ten; Wang, J. ; Leeuwen, F.W.B. van; Velders, A.H. - \ 2017
    Nanoscale 9 (2017)47. - ISSN 2040-3364 - p. 18619 - 18623.

    The hierarchically controlled synthesis and characterization of self-assembling macromolecules and particles are key to explore and exploit new nanomaterials. Here we present a versatile strategy for constructing particle-in-a-box-in-a-box systems by assembling dendrimer-encapsulated gold nanoparticles (DENs) into dendrimicelles. This is realized by combining positively charged PAMAM dendrimers with a negative-neutral block copolymer. The number of particles per dendrimicelle can be controlled by mixing DENs with empty PAMAM dendrimers. The dendrimicelles are stable in solution for months and provide improved resistance for the nanoparticles against degradation. The dendrimicelle strategy provides a flexible platform with a plethora of options for variation in the type of nanoparticles, dendrimers and block copolymers used, and hence is tunable for applications ranging from nanomedicine to catalysis.

    Size-Sorting and Pattern Formation of Nanoparticle-Loaded Micellar Superstructures in Biconcave Thin Films
    Hove, Jan Bart ten; Wang, Junyou ; Oosterom, Matthias N. van; Leeuwen, Fijs W.B. Van; Velders, Aldrik H. - \ 2017
    ACS Nano 11 (2017)11. - ISSN 1936-0851 - p. 11225 - 11231.
    Biconcave thin water layers represent a template to induce organization of supramolecular structures into ordered monolayers. Here we show how micelles form extensive micrometer-sized pseudo-2D superstructures that reveal size-sorting and geometric pattern formation, as shown by cryo-transmission electron microscopy (cryoTEM). Electron-rich gold particles inside the micelles facilitate direct visualization and determination of size, composition, and ordering of the micellar assemblies over multiple length scales. Some of the patterns observed show intriguing geometric patterns for superstructures, including Fibonacci-like, double-spiral domains that also appear in, for example, sunflower seed head patterns.
    Tropische vis in Nederlandse zee
    Couperus, A.S. - \ 2017
    All-Aqueous Synthesis of Silica-Encapsulated Quantum Dots with Functional Shells
    Feng, Huanhuan ; Hove, Jan Bart ten; Zheng, Tingting ; Velders, Aldrik H. ; Sprakel, Joris - \ 2017
    European Journal of Inorganic Chemistry 44 (2017). - ISSN 1434-1948 - p. 5152 - 5157.
    Encapsulation - Luminescence - Materials science - Quantum dots - Surface functionalization

    We present a simple yet versatile method for encapsulating water-dispersed quantum dots (QDs) in a silica shell. As our approach, does not require ligand exchange, the colloidal stability of the quantum dots is maintained throughout the process, which results in monodisperse core-shell particles of individual quantum dots with a well-defined silica shell whose thickness can be accurately controlled. While other methods often result in a reduction of luminescence, our approach can retain all or even increases the quantum efficiency of the semiconductor dots. We also show how amine-functional groups can be expressed at the surface of the silica shell, while retaining QD photoluminescence properties, allowing further surface functionalization. Finally, we demonstrate the versatility of this strategy by including dopants into the silica shells to tailor the spectral response of the core-shell particles by energy transfer.

    Auxin response cell-autonomously controls ground tissue initiation in the early Arabidopsis embryo
    Moller, Barbara ; Hove, Colette A. ten; Xiang, Daoquan ; Williams, Nerys ; López, Lorena González ; Yoshida, Saiko ; Smit, Margo ; Datla, Raju ; Weijers, Dolf - \ 2017
    Proceedings of the National Academy of Sciences of the United States of America 114 (2017)12. - ISSN 0027-8424 - p. E2533 - E2539.
    Auxin. - Embryogenesis - Ground tissue - Pattern formation - Plant development

    Plant organs are typically organized into three main tissue layers. The middle ground tissue layer comprises the majority of the plant body and serves a wide range of functions, including photosynthesis, selective nutrient uptake and storage, and gravity sensing. Ground tissue patterning and maintenance in Arabidopsis are controlled by a well-established gene network revolving around the key regulator SHORT-ROOT (SHR). In contrast, it is completely unknown how ground tissue identity is first specified from totipotent precursor cells in the embryo. The plant signaling molecule auxin, acting through AUXIN RESPONSE FACTOR (ARF) transcription factors, is critical for embryo patterning. The auxin effector ARF5/MONOPTEROS (MP) acts both cell-autonomously and noncell-autonomously to control embryonic vascular tissue formation and root initiation, respectively. Here we show that auxin response and ARF activity cell-autonomously control the asymmetric division of the first ground tissue cells. By identifying embryonic target genes, we show that MP transcriptionally initiates the ground tissue lineage and acts upstream of the regulatory network that controls ground tissue patterning and maintenance. Strikingly, whereas the SHR network depends on MP, this MP function is, at least in part, SHR independent. Our study therefore identifies auxin response as a regulator of ground tissue specification in the embryonic root, and reveals that ground tissue initiation and maintenance use different regulators and mechanisms. Moreover, our data provide a framework for the simultaneous formation of multiple cell types by the same transcriptional regulator.

    Towards guidelines for designing parks of the future
    Klemm, Wiebke ; Hove, Bert van; Lenzholzer, Sanda ; Kramer, Henk - \ 2017
    Urban Forestry and Urban Greening 21 (2017). - ISSN 1618-8667 - p. 134 - 145.
    Climate change adaptation - Climate-responsive design - Evidence-based landscape architecture - Heat wave - Public park - Thermal comfort
    This study investigated human behaviour in parks in order to develop spatially explicit design guidelines considering future climate conditions in moderate climates. Fieldwork was carried out in two parks (in Utrecht and Wageningen, the Netherlands) during summer and tropical days (Ta max > 25 °C and > 30 °C, respectively), the latter representing future climate conditions. Behavioural responses (park attendance, spatio-temporal user patterns) and thermal perception of resting park visitors were studied through unobtrusive observations (N = 11337) and surveys (N = 317). Outcomes were related to air temperature (Ta) of meteorological reference stations and spatial data on the vegetation structures of the parks. Observational data show that daily park attendance decreased with rising Ta max. Survey results indicate that resting park visitors perceived a high level of thermal comfort during all investigated days. Park visitors chose resting locations predominantly based on solar exposure conditions (sun, half shade, shade). Those solar exposure preferences were significantly related to Ta: with increased Ta the number of park visitors in the shade increased and decreased in the sun (p < 0.001) with a tipping point of 26 °C. These results indicate that parks in moderate climates may guarantee a high level of thermal comfort, even on tropical days, if a variety of solar exposure conditions is guaranteed. A ratio of 40% sun, 20% half shade and 40% shade in parks was derived from spatio-temporal user patterns, which appear to accommodate preferences of resting park visitors under summer and tropical thermal conditions and on various daytimes. These results and a spatial typology of tree configurations for microclimatic variety provide direction for designing future parks: they need to offer a wide range of sun-exposed, half shaded and shaded places to accommodate for different user needs and future climate conditions.
    Carbon accounting using flux measurements
    Elbers, J.A. ; Kleingeld, Eva ; Jacobs, Cor ; Hove, L.W.A. van; Moors, E.J. - \ 2016
    Transcriptional Analysis of serk1 and serk3 coreceptor mutants
    Esse, Wilma van; Hove, Colette A. ten; Guzzonato, Francesco ; Esse, Peter van; Boekschoten, Mark ; Ridder, Lars ; Vervoort, Jacques ; Vries, Sacco C. de - \ 2016
    Plant Physiology 172 (2016)4. - ISSN 0032-0889 - p. 2516 - 2529.

    Somatic embryogenesis receptor kinases (SERKs) are ligand-binding coreceptors that are able to combine with different ligandperceiving receptors such as BRASSINOSTEROID INSENSITIVE1 (BRI1) and FLAGELLIN-SENSITIVE2. Phenotypical analysis of serk single mutants is not straightforward because multiple pathways can be affected, while redundancy is observed for a single phenotype. For example, serk1serk3 double mutant roots are insensitive toward brassinosteroids but have a phenotype different from bri1 mutant roots. To decipher these effects, 4-d-old Arabidopsis (Arabidopsis thaliana) roots were studied using microarray analysis. A total of 698 genes, involved in multiple biological processes, were found to be differentially regulated in serk1-3serk3-2 double mutants. About half of these are related to brassinosteroid signaling. The remainder appear to be unlinked to brassinosteroids and related to primary and secondary metabolism. In addition, methionine-derived glucosinolate biosynthesis genes are up-regulated, which was verified by metabolite profiling. The results also show that the gene expression pattern in serk3-2 mutant roots is similar to that of the serk1-3serk3-2 double mutant roots. This confirms the existence of partial redundancy between SERK3 and SERK1 as well as the promoting or repressive activity of a single coreceptor in multiple simultaneously active pathways.

    Voorbij verbergen of vieren
    Hoogsteyns, M. ; Horst, H.M. van der - \ 2016
    In: Disability Studies in de Lage Landen / van Hove, Geert, Cardol, Mieke, Schippers, Alice, De Schauwer, Elisabeth, Apeldoorn/Antwerpen : Garant Uitgevers - ISBN 9789044134025 - p. 111 - 129.
    Molecular characterization of arabidopsis GAL4/UAS enhancer trap lines identifies novel cell-type-specific promoters
    Radoeva, Tatyana ; Hove, C.A. ten; Saiga, Shunsuke ; Weijers, Dolf - \ 2016
    Plant Physiology 171 (2016)2. - ISSN 0032-0889 - p. 1169 - 1181.
    Cell-type-specific gene expression is essential to distinguish between the numerous cell types of multicellular organism. Therefore, cell-type-specific gene expression is tightly regulated and for most genes RNA transcription is the central point of control. Thus, transcriptional reporters are broadly used markers for cell identity. In Arabidopsis (Arabidopsis thaliana), a recognized standard for cell identities is a collection of GAL4/UAS enhancer trap lines. Yet, while greatly used, very few of them have been molecularly characterized. Here, we have selected a set of 21 frequently used GAL4/UAS enhancer trap lines for detailed characterization of expression pattern and genomic insertion position. We studied their embryonic and postembryonic expression domains and grouped them into three groups (early embryo development, late embryo development, and embryonic root apical meristem lines) based on their dominant expression. We show that some of the analyzed lines are expressed in a domain often broader than the one that is reported. Additionally, we present an overview of the location of the T-DNA inserts of all lines, with one exception. Finally, we demonstrate how the obtained information can be used for generating novel cell-type-specific marker lines and for genotyping enhancer trap lines. The knowledge could therefore support the extensive use of these valuable lines.
    Assembling quantum dots via critical Casimir forces
    Marino, Emanuele ; Kodger, T.E. ; Hove, Jan Bart ten; Velders, A.H. ; Schall, Peter - \ 2016
    Solar Energy Materials and Solar Cells 158 (2016). - ISSN 0927-0248 - p. 154 - 159.
    Assembly - Casimir force - Nanocrystals - Nanomanipulation - Quantum dots

    Programmed assembly of colloidal inorganic nanocrystal superstructures is crucial for the realization of future artificial solids as well as present optoelectronic applications. Here, we present a new way to assemble quantum dots reversibly using binary solvents. By tuning the temperature and composition of the binary solvent mixture, we achieve reversible aggregation of nanocrystals in solution induced by critical Casimir forces. We study the temperature-sensitive quantum-dot assembly with dynamic light scattering. We show that careful screening of the electrostatic repulsion by adding salt provides a further parameter to tune the reversible assembly.

    Bultrug steeds vaker gespot
    Leopold, Mardik - \ 2015
    MMP-2/9-specific activatable lifetime imaging agent
    Rood, Marcus T.M. ; Raspe, Marcel ; Hove, Jan Bart ten; Jalink, Kees ; Velders, A.H. ; Leeuwen, F.W.B. van - \ 2015
    Sensors 15 (2015)5. - ISSN 1424-8220 - p. 11076 - 11091.
    Enzymatic activation - Fluorescence - FRET - Iridium - Lifetime imaging - Luminescence - MMP

    Optical (molecular) imaging can benefit from a combination of the high signal-to-background ratio of activatable fluorescence imaging with the high specificity of luminescence lifetime imaging. To allow for this combination, both imaging techniques were integrated in a single imaging agent, a so-called activatable lifetime imaging agent. Important in the design of this imaging agent is the use of two luminophores that are tethered by a specific peptide with a hairpin-motive that ensured close proximity of the two while also having a specific amino acid sequence available for enzymatic cleavage by tumor-related MMP-2/9. Ir(ppy)3 and Cy5 were used because in close proximity the emission intensities of both luminophores were quenched and the influence of Cy5 shortens the Ir(ppy)3 luminescence lifetime from 98 ns to 30 ns. Upon cleavage in vitro, both effects are undone, yielding an increase in Ir(ppy)3 and Cy5 luminescence and a restoration of Ir(ppy)3 luminescence lifetime to 94 ns. As a reference for the luminescence activation, a similar imaging agent with the more common Cy3-Cy5 fluorophore pair was used. Our findings underline that the combination of enzymatic signal activation with lifetime imaging is possible and that it provides a promising method in the design of future disease specific imaging agents.

    Hoeveel water verdampt de stad?
    Jacobs, C.M.J. ; Elbers, J.A. ; Moors, E.J. ; Hove, L.W.A. van - \ 2015
    Water Matters : Kenniskatern voor Waterprofessionals - Dutch edition (2015)oktober. - p. 34 - 37.
    evaporatie - waterbeheer - stedelijke gebieden - stedelijke samenleving - waterbehoefte - klimaatverandering - zoet water - evaporation - water management - urban areas - urban society - water requirements - climatic change - fresh water
    Hoeveel water verliest een stad door verdamping? Wat betekent dat? En is dat proces van verdamping te beïnvloeden? Onderzoek van Alterra Wageningen UR levert inzichten op die voor de steden steeds belangrijker zullen worden.
    Tripple-I method empowers professional vocational education students in mobilizing their assets
    Dierx, J. ; Detaille, S. ; Boonekamp, G. ; Peters, V. ; Cuperus, J. ; Hove, P. van; Vaandrager, L. - \ 2015
    In: 8th European Public Health Conference, Health in Europe - from global to local policies, Methods and practices. - - p. 57 - 57.
    Temperature controlled sequential gelation in composite microgel suspensions
    Appel, J. ; Lange, N. de; Kooij, H.M. van der; Laar, T.X. van de; Hove, J.B. ten; Kodger, T.E. ; Sprakel, J.H.B. - \ 2015
    Particle and Particle Systems Characterization 32 (2015)7. - ISSN 0934-0866 - p. 764 - 770.
    attractive particles - liquid - gels
    Depending on the volume fraction and interparticle interactions, colloidal suspensions can exhibit a variety of physical states, ranging from fluids, crystals, and glasses to gels. For microgel particles made of thermoresponsive polymers, both parameters can be tuned using environmental parameters such as temperature and ionic strength, making them excellent systems to experimentally study state transitions in colloidal suspensions. Using a simple two-step synthesis it is shown that the properties of composite microgels, with a fluorescent latex core and a responsive microgel shell, can be finely tuned. With this system the transitions between glass, liquid, and gel states for suspensions composed of a single species are explored. Finally, a suspension of two species of microgels is demonstrated, with different transition temperatures, gels in a sequential manner. Upon increasing temperature a distinct core–sheath structure is formed with a primary gel composed of the species with lowest transition temperature, which acts as a scaffold for the aggregation of the second species.
    Building a plant: cell fate specification in the early Arabidopsis embryo
    Hove, C.A. ten; Lu, Kuan-Ju ; Weijers, D. - \ 2015
    Development 142 (2015). - ISSN 0950-1991 - p. 420 - 430.
    homeodomain-leucine-zipper - apical-basal axis - layer-specific gene - box protein tir1 - transcription factor - vascular development - early embryogenesis - pattern-formation - shoot meristem - f-box
    Embryogenesis is the beginning of plant development, yet the cell fate decisions and patterning steps that occur during this time are reiterated during development to build the post-embryonic architecture. In Arabidopsis, embryogenesis follows a simple and predictable pattern, making it an ideal model with which to understand how cellular and tissue developmental processes are controlled. Here, we review the early stages of Arabidopsis embryogenesis, focusing on the globular stage, during which time stem cells are first specified and all major tissues obtain their identities. We discuss four different aspects of development: the formation of outer versus inner layers; the specification of vascular and ground tissues; the determination of shoot and root domains; and the establishment of the first stem cells.
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