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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Fungal footwear and orange peel fabrics : the sustainable catwalk
Poldner, Kim ; Houthoff, Iris ; Oever, Martien van den - \ 2018
biobased economy - clothing - biomass - fibres - biobased materials - chemistry
Which energy can be obtained from using poop?
Weusthuis, R.A. - \ 2017
Wageningen :
biobased economy - chemistry - biobased chemistry - biomass - bioenergy
Which new energy sources can be used in a biobased society?
Conductometer Schott
Bom, Jesse ; Dijksman, J.A. ; Lageschaar, Luuk ; Galen, Martijn van; Hoogendam, C.W. ; Wegh, R.A.J. - \ 2016
Wageningen : Wageningen UR
geleidingsvermogen - instrumenten (meters) - meetinstrumenten - chemie - conductivity - instruments - indicating instruments - chemistry
Instructievideo over het gebruik van de Schott Conductometer
Conductometer Knick
Bom, Jesse ; Dijksman, J.A. ; Lageschaar, Luuk ; Galen, Martijn van; Hoogendam, C.W. ; Wegh, R.A.J. - \ 2016
Wageningen : Wageningen UR
geleidingsvermogen - chemie - meetinstrumenten - conductivity - chemistry - indicating instruments
Instructievideo over het gebruik van de Knick Conductometer
Bom, Jesse ; Dijksman, J.A. ; Lageschaar, Luuk ; Galen, Martijn van; Hoogendam, C.W. ; Wegh, R.A.J. - \ 2016
Wageningen : Wageningen UR
glaswerk - laboratoria - laboratoriumuitrusting - chemie - glassware - laboratories - laboratory equipment - chemistry
Instructievideo over de verschillende soorten glaswerk die gebruikt worden in een laboratorium. Waarvoor gebruik je de verschillende soorten glaswerk en wat is hun nauwkeurigheid.
Metrohm Buret
Bom, Jesse ; Dijksman, J.A. ; Lageschaar, Luuk ; Galen, Martijn van; Hoogendam, C.W. ; Wegh, R.A.J. - \ 2016
Wageningen : Wageningen UR
titratie - chemie - instrumenten (meters) - titration - chemistry - instruments
Instructievideo over het gebruik van de Metrohm Buret
Digitale Buret
Bom, Jesse ; Dijksman, J.A. ; Lageschaar, Luuk ; Galen, Martijn van; Hoogendam, C.W. ; Wegh, R.A.J. - \ 2016
Wageningen : Wageningen UR
titratie - chemie - titration - chemistry
Instructievideo over het gebruik van de digitale buret
Een chemicus kan de wereld veranderen : Harriëtte Bos : programmamanager Biobased Economy bij Wageningen UR
Bos, Harriette - \ 2016
career choice - chemists - chemistry - biobased economy - technical progress - innovations - interviews - research workers
Atmospheric Boundary Layer, Integrating Air Chemistry and Land Interactions
Vilà-Guerau De Arellano, J. ; Heerwaarden, C.C. van; Stratum, B.J.H. van; Dries, C.L.A.M. van den - \ 2015
New York : Cambridge University Press - ISBN 9781107090941 - 265
atmosferische grenslaag - atmosfeer - fysica - chemie - plantenfysiologie - vegetatie - bodemkunde - meteorologie - agrometeorologie - hydrologie - studieboeken - atmospheric boundary-layer - atmosphere - physics - chemistry - plant physiology - vegetation - soil science - meteorology - agricultural meteorology - hydrology - textbooks
This textbook provides an introduction to the interactions between the atmosphere and the land for advanced undergraduate and graduate students and a reference text for researchers in atmospheric physics and chemistry, hydrology, and plant physiology. The combination of the book, which provides the essential theoretical concepts, and the associated interactive Chemistry Land-surface Atmosphere Soil Slab (CLASS) software, which provides hands-on practical exercises and allows students to design their own numerical experiments, will prove invaluable for learning about many aspects of the soil-vegetation-atmosphere system. This book has a modular and flexible structure, allowing instructors to accommodate it to their own learning-outcome needs.
Polymer organogelation with chitin and chitin nanocrystals
Nikiforidis, C.V. ; Scholten, E. - \ 2015
RSC Advances : An international journal to further the chemical sciences 5 (2015)47. - ISSN 2046-2069 - p. 37789 - 37799.
mechanical characterization - supramolecular gels - lecithin organogel - molecular-weight - edible oils - chitosan - derivatives - morphology - chemistry - mixtures
In this paper, we show that biodegradable and biocompatible organogels can be formed with chitin as the filler material and triglycerides as the continuous hydrophobic phase. When crude chitin was used, a large degree of aggregation was observed that prevented the formation of stable organogels. Two approaches were used to diminish this degree of aggregation and increase the stability. Either surfactants were used to increase the dispersability of the crude chitin, or the crude chitin was transformed into smaller rod-like nanocrystals by acid hydrolysis. Both approaches led to the formation of stable organogels with storage moduli up to 106 Pa for high chitin concentrations (20 wt%). Three different types of surfactants were used, namely phosphatidylcholine, enzymatically modified phosphatidylcholine and sorbitan monostearate (Span 60). The choice of surfactant has a large influence on the gel strength and the temperature sensitivity of the gels. With chitin nanocrystals, in the presence of surfactants, larger gel strengths were observed for lower concentrations (1-10 wt%), indicating more efficient packing of the particles. Gels were stable even after addition of considerable amounts of water up to 25 wt%. The increase in gel strength in the presence of water (storage modulus) was most likely an effect of the water absorption ability of chitin that increased the effective volume fraction of the fillers.
‘the chemical industry is the driving force’
Sanders, Johan - \ 2014
biobased economy - biobased chemistry - biomass - chemistry - biofuels - renewable energy
Diet selection of goats depends on season: roles of plant physical and chemical traits
Mkhize, N.R. ; Scogings, P.F. ; Nsahlai, I.V. ; Dziba, L.E. - \ 2014
African Journal of Range and Forage Science 31 (2014)3. - ISSN 1022-0119 - p. 209 - 214.
south-african savanna - woody-plants - intake rates - subtropical savanna - browsing ruminants - feeding-behavior - semiarid savanna - capra-hircus - nguni goats - chemistry
This paper reports on diet selection of goats offered six browse species (i.e. Acacia natalitia [Vachellia natalitia], Acacia nilotica [Vachellia nilotica], Dichrostachys cinerea, Grewia occidentalis, Gymnosporia maranguensis and Scutia myrtina) commonly found in moist Zululand thornveld. The hypotheses tested were: (1) plant species and season affect diet selection, (2) physical traits such as leaf phenology, spinescence, shoot morphology and leaf size affect selection, and (3) selection is related to tannins, fibre and protein in ways that indicate nutrient maximisation. Six 2-year-old castrated indigenous goats weighing an average of 26 kg each were individually penned and maintained on a basal diet of pellets and grass hay. Six branches were offered simultaneously to individual goats and intake per branch recorded and used as an index for diet selection. Diet selection was significantly influenced by interactions between plant species and season. Scutia myrtina and Grewia occidentalis were consistently the most preferred species, whereas Gynmosporia maranguensis and Acacia nilotica were least preferred throughout the seasons. Goats preferred broad-leaf and long-shoot species over fine-leaf and short-shoot species across all seasons. These results suggest that short-term diet selection in subhumid areas is not as strongly influenced by leaf phenology and plant chemistry as in semi-arid savannas.
Sequential effects of root and foliar herbivory on aboveground and belowground induced plant defense responses and insect performance
Wang, M. ; Biere, A. ; Putten, W.H. van der; Bezemer, T.M. - \ 2014
Oecologia 175 (2014)1. - ISSN 0029-8549 - p. 187 - 198.
deterrent iridoid glycosides - mediated interactions - specialist herbivore - chemical defense - lanceolata l - induction - generalist - damage - age - chemistry
Plants are often simultaneously or sequentially attacked by multiple herbivores and changes in host plants induced by one herbivore can influence the performance of other herbivores. We examined how sequential feeding on the plant Plantago lanceolata by the aboveground herbivore Spodoptera exigua and the belowground herbivore Agriotes lineatus influences plant defense and the performance of both insects. Belowground herbivory caused a reduction in the food consumption by the aboveground herbivore independent of whether it was initiated before, at the same time, or after that of the aboveground herbivore. By contrast, aboveground herbivory did not significantly affect belowground herbivore performance, but significantly reduced the performance of later arriving aboveground conspecifics. Interestingly, belowground herbivores negated negative effects of aboveground herbivores on consumption efficiency of their later arriving conspecifics, but only if the belowground herbivores were introduced simultaneously with the early arriving aboveground herbivores. Aboveground–belowground interactions could only partly be explained by induced changes in an important class of defense compounds, iridoid glycosides (IGs). Belowground herbivory caused a reduction in IGs in roots without affecting shoot levels, while aboveground herbivory increased IG levels in roots in the short term (4 days) but only in the shoots in the longer term (17 days). We conclude that the sequence of aboveground and belowground herbivory is important in interactions between aboveground and belowground herbivores and that knowledge on the timing of exposure is essential to predict outcomes of aboveground–belowground interactions.
Observational evidence for interhemispheric hydroxyl-radical parity
Patra, P.K. ; Krol, M.C. ; Montzka, S.A. ; Arnold, T. ; Atlas, E.L. ; Lintner, B.R. ; Stephens, B.B. ; Xiang, B. - \ 2014
Nature 513 (2014)7517. - ISSN 0028-0836 - p. 219 - 223.
atmospheric hydroxyl - sulfur-hexafluoride - methyl chloroform - tropospheric oh - model - variability - transport - chemistry - climate - methane
The hydroxyl radical (OH) is a key oxidant involved in the removal of air pollutants and greenhouse gases from the atmosphere1, 2, 3. The ratio of Northern Hemispheric to Southern Hemispheric (NH/SH) OH concentration is important for our understanding of emission estimates of atmospheric species such as nitrogen oxides and methane4, 5, 6. It remains poorly constrained, however, with a range of estimates from 0.85 to 1.4 (refs 4, 7,8,9,10). Here we determine the NH/SH ratio of OH with the help of methyl chloroform data (a proxy for OH concentrations) and an atmospheric transport model that accurately describes interhemispheric transport and modelled emissions. We find that for the years 2004–2011 the model predicts an annual mean NH–SH gradient of methyl chloroform that is a tight linear function of the modelled NH/SH ratio in annual mean OH. We estimate a NH/SH OH ratio of 0.97 ± 0.12 during this time period by optimizing global total emissions and mean OH abundance to fit methyl chloroform data from two surface-measurement networks and aircraft campaigns11, 12, 13. Our findings suggest that top-down emission estimates of reactive species such as nitrogen oxides in key emitting countries in the NH that are based on a NH/SH OH ratio larger than 1 may be overestimated.
Supramolecular assembly of self-healing nanocomposite hydrogels
Gerth, M. ; Bohdan, M.A. ; Fokkink, R.G. ; Voets, I.K. ; Gucht, J. van der; Sprakel, J.H.B. - \ 2014
Macromolecular Rapid Communications 35 (2014)24. - ISSN 1022-1336 - p. 2065 - 2070.
poly(ethylene glycol) - aqueous-solution - gel transition - terpyridine - coordination - chemistry - gelation - driven - light
Hierarchical self-assembly of transient composite hydrogels is demonstrated through a two-step, orthogonal strategy using nanoparticle tectons interconnected through metal–ligand coordination complexes. The resulting materials are highly tunable with moduli and viscosities spanning many orders of magnitude, and show promising self-healing properties, while maintaining complete optical transparency.
Inter-laboratory comparison study for pyrrolizidine alkaloids in animal feed using spiked and incurred material
Nijs, W.C.M. de; Elbers, I.J.W. ; Mulder, P.P.J. - \ 2014
Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 31 (2014)2. - ISSN 1944-0049 - p. 288 - 299.
mass-spectrometry - senecio-vernalis - plants - food - toxicity - jacobaea - vulgaris - milk - chemistry - honey
Pyrrolizidine alkaloids (PAs) are hepatotoxic metabolites produced by plants. PAs in animal feed can cause acute or chronic intoxications in animals and can be transferred to milk. An inter-laboratory comparison study among 12 laboratories, using their own methods of analysis, was conducted for the detection and quantification of PAs in animal feed. The participants were asked to quantify PAs in a blank test sample, a blank test sample to be spiked with a provided spiking mixture of seven PA standards, and a test sample contaminated with common groundsel (Senecio vulgaris). Ten of the participating laboratories used an LC-MS/MS method, one used an LC-ToF-MS method, and one used a GC-MS method. None of the laboratories reported false-negative samples, while two laboratories reported false-positive results in the blank sample. z-scores were calculated for each laboratory for seven PAs in test samples B and C. z-scores varied considerably between laboratories for the concentrations of the free bases and less for the N-oxides, probably due to the lower levels of the free bases as compared with the N-oxides in the contaminated feed. Questionable or unsatisfactory results for the z-scores were obtained for 8% of the cases for the spiked sample and for 12% of the incurred sample. Three laboratories scored consequently positive or negative results. No preferred method for quantification of PAs in feed could be identified within the methods used for this study due to the relatively small number of participants. It was concluded that this inter-laboratory study shows that the methods used for PA detection need further development for accurate estimation of PAs in contaminated feed.
Biochars produced from individual grassland species differ in their effect on plant growth
Voorde, T.F.J. van de; Noppen, F. van; Nachenius, R.W. ; Prins, W. ; Mommer, L. ; Bezemer, T.M. ; Groenigen, J.W. van - \ 2014
Basic and Applied Ecology 15 (2014)1. - ISSN 1439-1791 - p. 18 - 25.
litter decomposition - soil - chemistry - jacobaea - vulgaris - quality - traits - rates - biota
Biochar, pyrolyzed biomass, has been shown to be a promising way to improve plant productivity and soil quality. Biochar characteristics and its effect on plant performance depend strongly on the type of feedstock from which it is made. However, whether biochars produced from individual grassland species differ in their characteristics and effects on plant growth when applied to soil is poorly understood. The aim of this study was to examine how soil application of pyrolyzed and non-pyrolyzed biomass originating from different grassland species influences plant performance. We measured the growth of the forb Jacobaea vulgaris in soil amended with pyrolyzed or non-pyrolyzed biomass of seven different plant species, and in control soil without amendments. The characteristics (nutrient content, C:N) and effects on plant growth of both pyrolyzed and non-pyrolyzed biomass differed significantly between species from which the biomass originated (‘feedstock species’). For most feedstock species there was no relationship between the effects that the pyrolyzed and the non-pyrolyzed biomass had on plant performance. Our results show that pyrolyzed grassland species differ in their characteristics and their effect on plant growth when amended to soil. This shows that it is important to test what the effect of pyrolysing a chosen feedstock is on a species before applying it on a larger scale and that potentially biochar with predefined effects could be designed for specific purposes.
Hydrolysates of glycated and heat treated peanut 7S globulin (Ara h 1) modulate human gut microbiota proliferation, survival and adhesion
Teodorowicz, M. ; Swiatecka, D. ; Savelkoul, H.F.J. ; Wichers, H.J. ; Kostyra, E. - \ 2014
Journal of Applied Microbiology 116 (2014)2. - ISSN 1364-5072 - p. 424 - 434.
maillard reaction-products - intestinal microbiota - in-vitro - proteins - health - allergen - differentiation - prevalence - chemistry - barrier
Aims - Evaluation of an effect of glycation of Ara h 1 on proliferation and survival rate and adhesion of intestinal Enterococcus faecalis, Escherichia coli and Lactobacillus acidophilus. Methods and Results - Pure Ara h 1 heated at three different temperature conditions (G37°C, G60°C and C145°C) in the presence or absence of glucose was subjected to enzymatic hydrolysis. Impacts of Ara h 1 hydrolysates on the bacterial proliferation, survival rate and adhesion to Caco-2 cells in mono and heterogeneous cultures were studied with fluorescent techniques: DAPI, LIVE/DEAD staining and FISH. Examined hydrolysates hindered proliferation of E. coli and E. faecalis with simultaneous decrease in their survival. Maillard reaction (MR, glycation) of Ara h 1 did not alter the effect of hydrolysates on bacterial proliferation rate. Hydrolysates modified at 60°C and 145°C with glucose altered the profile of immobilized bacteria, mostly by lowering the number of adhering E. coli and promoting the adhesion of bacteria from genera Lactobacillus and Enterococcus. Conclusions - Ara h1 hydrolysates processed in various ways demonstrated their strong modulatory effect on bacterial proliferation, survival rate and adhesion. Significance and Impact of Study - Reducing the adhesion of opportunistic bacteria by hydrolysates of Ara h 1 glycated at 60°C and 145°C, together with modulation of immobilization of beneficial lactobacilli and enterococci, may be of relevance in terms of the physiological status of the intestinal barrier
Nonlinear Amplification of a Supramolecular Complex at a Multivalent Interface
Hsu, S.H. ; Yilmaz, M.D. ; Reinhoudt, D.N. ; Velders, A.H. ; Huskens, J. - \ 2013
Angewandte Chemie-International Edition 52 (2013)2. - ISSN 1433-7851 - p. 714 - 719.
self-assembled monolayers - molecular printboards - chemistry - binding - membrane - nanostructures - organization - selection - discrete - peptides
Competition with a monovalent cyclodextrin host (blue cones) in solution drives the multivalent binding of a Eu3+ complex and a sensitizer molecule to cyclodextrin monolayers through a nonlinear self-assembly process. Adamantyl groups (light-blue spheres) are attached to the EDTA ligand (black) and the antenna molecule (orange), which has a carboxylate group for coordination to the Eu3+ ion (yellow or red in free or complexed form, respectively).
Emission ratio and isotopic signatures of molecular hydrogen emissions from tropical biomass burning
Haumann, F.A. ; Batenburg, A.M. ; Pieterse, G. ; Gerbig, C. ; Krol, M.C. ; Rockmann, T. - \ 2013
Atmospheric Chemistry and Physics 13 (2013)18. - ISSN 1680-7316 - p. 9401 - 9413.
atmospheric hydrogen - assimilation system - land-surface - amazon basin - trace gases - tall tower - model tm5 - h-2 - chemistry - plants
In this study, we identify a biomass-burning signal in molecular hydrogen (H-2) over the Amazonian tropical rainforest. To quantify this signal, we measure the mixing ratios of H-2 and several other species as well as the H-2 isotopic composition in air samples that were collected in the BARCA (Balanco Atmosferico Regional de Carbono na Amazonia) aircraft campaign during the dry season. We derive a relative H-2 emission ratio with respect to carbon monoxide (CO) of 0.31 +/- 0.04 ppb ppb(-1) and an isotopic source signature of -280 +/- 41 parts per thousand in the air masses influenced by tropical biomass burning. In order to retrieve a clear source signal that is not influenced by the soil uptake of H-2, we exclude samples from the atmospheric boundary layer. This procedure is supported by data from a global chemistry transport model. The Delta H-2/Delta CO emission ratio is significantly lower than some earlier estimates for the tropical rainforest. In addition, our results confirm the lower values of the previously conflicting estimates of the H-2 isotopic source signature from biomass burning. These values for the emission ratio and isotopic source signatures of H-2 from tropical biomass burning can be used in future bottom-up and top-down approaches aiming to constrain the strength of the biomass-burning source for H-2. Hitherto, these two quantities relied only on combustion experiments or on statistical relations, since no direct signal had been obtained from in-situ observations.
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