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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    Disparities in cancer-related healthcare among people with intellectual disabilities:A population-based cohort study with health insurance claims data
    Cuypers, Maarten ; Tobi, Hilde ; Huijsmans, Cornelis A.A. ; Gerwen, Lieke van; Hove, Michiel ten; Weel, Chris van; Kiemeney, Lambertus A.L.M. ; Naaldenberg, Jenneken ; Leusink, Geraline L. - \ 2020
    Cancer Medicine (2020). - ISSN 2045-7634
    early detection of cancer - healthcare disparities - hospital - intellectual disability - neoplasms - oncology service

    Background: Concerns have been raised about the accessibility and quality of cancer-related care for people with intellectual disabilities (ID). However, there is limited insight into cancer incidence and the utilization of cancer care at the ID population level to inform targeted cancer control strategies. Therefore, we aimed to examine differences in the utilization of cancer-related care between people with and without ID, identified through diagnostic codes on health insurance claims. Methods: In a population-based cohort study, Dutch individuals of all ages who received residential care through the Chronic Care Act due to an ID (n = 65 183) and an age and sex-matched sample of persons without ID (1:2 ratio), who were cancer-free at enrollment in 2013 were followed through 2015. Incidence rates (IRs) of newly started cancer care and IR ratios (IRRs) with 95% CIs were used to compare groups. Separate analyses were performed per cancer type. Results: Individuals with ID received less cancer-related care than individuals without (IRR = 0.64, 95% CI 0.62-0.66). Differences increased with age and were larger for females than for males. Utilization of care for cancers within the national screening program (female breast, cervical, and colon cancer) was lower for people with ID compared to people without ID. Conclusion: Cancer may be underdiagnosed and/or undertreated in people with ID, or cancer is truly less prevalent in this population. In particular, the differences detected between males and females with ID, and the potential underutilization of national screening programs, require urgent follow-up investigations.

    Hydrogen Bonding in Phosphine Oxide/Phosphate-Phenol Complexes
    Cuypers, R. ; Sudhölter, E.J.R. ; Zuilhof, H. - \ 2010
    ChemPhysChem 11 (2010)10. - ISSN 1439-4235 - p. 2230 - 2240.
    solvent-impregnated resins - isothermal titration calorimetry - plesset perturbation-theory - log k-values - density functionals - bonded complexes - noncovalent interactions - interaction energies - binding-energies - water clusters
    To develop a new solvent-impregnated resin (SIR) system for the removal of phenols and thiophenols from water, complex formation by hydrogen bonding of phosphine oxides and phosphates is studied using isothermal titration calorimetry (ITC) and quantum chemical modeling. Six different computational methods are used: B3LYP, M06-2X, MP2, spin component-scaled (SCS) MP2 [all four with 6-311+G(d,p) basis set], a complete basis set extrapolation at the MP2 level (MP2/CBS), and the composite CBS-Q model. This reveals a range of binding enthalpies (¿H) for phenol–phosphine oxide and phenol–phosphate complexes and their thio analogues. Both structural (bond lengths/angles) and electronic elements (charges, bond orders) are studied. Furthermore, solvent effects are investigated theoretically by the PCM solvent model and experimentally via ITC. From our calculations, a trialkylphosphine oxide is found to be the most promising extractant for phenol in SIRs, yielding ¿H=-14.5 and -9.8 kcal¿mol-1 with phenol and thiophenol, respectively (MP2/CBS), without dimer formation that would hamper the phenol complexation. In ITC measurements, the ¿H of this complex was most negative in the noncoordinating solvent cyclohexane, and slightly less so in p–p interacting solvents such as benzene. The strongest binding is found for the dimethyl phosphate–phenol complex [-15.1 kcal¿mol-1 (MP2/CBS)], due to the formation of two H-bonds (PO···H-O- and P-O-H···O-H); however, dimer formation of these phosphates competes with complexation of phenol, and would thus hamper their use in industrial extractions. CBS-Q calculations display erroneous trends for sulfur compounds, and are found to be unsuitable. Computationally relatively cheap SCS-MP2 and M06-2X calculations did accurately agree with the much more elaborate MP2/CBS method, with an average deviation of less than 1 kcal¿mol-1
    Complexation of Phenol and Thiophenol by Amine N-Oxides: Isothermal Titration Caloritmetry and ab Initio Calculations
    Cuypers, R. ; Sukumaran, M. ; Marcelis, A.T.M. ; Sudhölter, E.J.R. ; Zuilhof, H. - \ 2010
    ChemPhysChem 11 (2010)16. - ISSN 1439-4235 - p. 3465 - 3473.
    solvent-impregnated resins - plesset perturbation-theory - hydrogen-bond strengths - noncovalent interactions - correlation energies - density functionals - aqueous-media - extraction - acid - dimers
    To develop a new solvent-impregnated resin (SIR) system for removal of phenols from water the complex formation of dimethyldodecylamine. N-oxide (DMDAO), trioctylamine N-oxide (TOAO), and tris(2-ethylhexyl)amine N-oxide (TEHAO) with phenol (PhOH) and thiophenol (PhSH) is studied To this end we use isothermal titration calorimetry (ITC) and quantum chemical modeling (on B3LYP/6 311G(d,p)-optimized geometries B3LYP/6-311+G(d,p), B3LYP/6311++ G(2d,2p), MP2/6-311 +G(d,p), and and spin component scaled (SCS) MP2/6-311+ G(d,p), M06-2X/6-311+G(d,p)//M06-2X/6311G(dp), MP2 with an extrapolation to the complete basis (MP2/CBS), as well as CBS-Q) The complexes are analyzed in terms of structural (e g, bond lengths) and electronic elements (e g, charges) Furthermore, complexation and,solvent effects (in benzene, toluene, and mesitylene) are investigated by ITC measurements, yielding binding constants K, enthalpies Delta H-0, Gibbs fre energies Delta G(0), and entropies Delta S-0 of complex formation, and stoichiometry N The ITC measurements revealed strong 1 1 complex formation between both DMDAO-PhOH and TOAO-PhOH The binding constant (K=1 7-5 7 x 10(4) M-1) drops markedly when water saturated toluene was used (K=5 8 x 10(3) M-1), and with, the solvent is shown to be relevant Quantum modeling confirms formation of stable 11 complexes with linear hydrogen bonds that weaken on attachment. of electron-withdrawing groups to the amine N-oxide moiety Modeling also showed that complexes with PhSH are much weaker than those with PhOH, and in fact too weak for ITC determination CBS-Q incorrectly predicts equal or even higher binding enthalpies for PhSH than for PhOH, which invalidates it as a benchmark for other calculations Data from the straightforward SCS-MP2 method without counterpoise correction show very good agreement with the MP2/CBS values
    Hydrogen bonding in the recovery of phenols and methyl-t-butyl ether : molecular modeling and calorimetry
    Cuypers, R. - \ 2010
    Wageningen University. Promotor(en): Han Zuilhof; Ernst Sudhölter. - [S.l. : S.n. - ISBN 9789085857754 - 189
    afvalwaterbehandeling - verwijdering - fenol - ethers - derivaten - harsen - extractie - waste water treatment - removal - phenol - ethers - derivatives - resins - extraction
    The purification of waste water is very important, for clean potable water is a common good and a necessity. Surface water purification is nowadays carried out on a massive industrial scale, and clean water is at our disposal virtually everywhere and always. However, cleaning industrial waste water can be a difficult task. Although apolar and slightly polar compounds can be removed from water relatively easily e.g. by extraction to an apolar phase, more polar pollutants like phenol and methyl-tert-butyl ether (MTBE), the two main compounds that this thesis deals with, cannot be removed as easily. A more effective method is therefore needed to clean water that is contaminated with either phenol or MTBE.
    Solvent-Impregnated Resins (SIRs) are porous polymer beads containing apolar organic extractant liquids. They are used as three-phase separation systems. When brought into contact with a SIR, a solute will preferentially partition from the aqueous phase into the impregnated solvent phase. A drawback to the use of solely the organic extraction liquid in SIRs is the limited solubility of more polar compounds like phenols and ethers in such a medium. In order to enhance extraction, complex-forming extractants can be added to the organic solvent. By means of complex formation inside the organic solvent, the overall equilibrium distribution can be shifted towards the SIR, with a concomitant enhancement of the extraction efficiency. A tight binding of the pollutant molecules to the extractant will eventually ensure high distribution coefficients. However, a moderate binding strength would enable a relatively easy regeneration of the complexing agent after a binding event, enabling multiple uses of the same compound.
    In this thesis hydrogen-bond (H-bond) complexation, a specific and strong yet reversible way of binding is investigated for phenol recovery and MTBE recovery from aqueous environments, involving the use of organic complexing agents that can be used inside the SIR to enhance the extraction. Potentially interesting compounds were investigated on a molecular scale by quantum chemical modeling methods and subsequent synthesis and physical characterization by primarily calorimetric means. H-bond complex formation has been evaluated and the important parameters determining the binding process have been described.
    After a general introduction in Chapter 1, Chapters 2 through 4 describe phenol complexation by several different classes of complexing agents. In Chapter 2, the binding of phenol and thiophenol by phosphine oxides, phosphates, and their thio-analogs was investigated. Modeling experiments, isothermal titration calorimetry (ITC) measurements, and liquid-liquid extraction experiments showed that, in principle, the binding affinity of the oxide compounds for phenol is high, whereas the sulfide compounds show only low affinity. In particular, the binding behavior of tri-n-octylphosphine oxide towards phenol and a series of electron-withdrawing group (EWG)-substituted phenols was studied, both in the presence and absence of water in the system. It was found that the presence of water in the system – as can be expected in industrial applications – yields lower binding affinities by as much as 60 %, but the binding stoichiometry remained specific and 1 : 1 complexes were still found. Electronic and steric effects were shown to play an important role in phenol binding in the investigated environment.
    In Chapter 3, these investigations were extended to the modeling of the full homologous series of mono-, di- and tri-substituted phosphine oxides and phosphates and their thio-analogs. Different modeling methods were used to investigate both structural and electronic elements. Dimethylphosphate was found to form the strongest complexes to the investigated phenols, but because this compound forms very strong homo-dimers in solution it cannot be used as an effective extractant. The SCS-MP2 method, that was relatively unexplored for H-bonding until now, was found to yield very accurate energy predictions, whereas the CBS-Q method was found to predict false binding affinities. Solvent effects are shown to immensely influence the binding behavior.
    Another, even stronger group of H-bond acceptors, amine-N-oxides, was investigated as described in Chapter 4. The binding properties for phenol and thiophenol with three different amine-N-oxides yielded very high binding affinities (up to 30 times higher than for the phosphine oxide compounds). Introduction of EWGs in the amine-N-oxides was shown to yield markedly lower binding affinities towards phenols, providing a handle to fine-tune the interaction and facilitating easier regeneration of the complexing agent in future SIR applications. Solvent effects and the influence of water in the system were investigated, and it was shown that they both influence the phenol binding strength. The results in Chapters 2 through 4 show that phosphates, phosphine oxides, and amine-N-oxides could all be used in future SIR extraction systems, and the choice between these classes of compounds can be made based on more detailed considerations.
    MTBE binding by several complexing agents was described in Chapter 5. A detailed modeling study of a number of different substituted phenols for MTBE binding was carried out, and the influence of solvents on the binding behavior was investigated, using a.o. the recently developed M06-2X functional and SMD solvent model. The investigated complexing agents were found to show moderate binding affinities to MTBE with binding strengths being closely linked to the acidity of the extractant. Steric effects and a proper consideration of entropic effects are also found to be important to yield successful binding of MTBE. In combination with the existing MTBE distribution coefficient for apolar phases, these moderate binding affinities were found to be able to enhance extraction, in principle, up to the point where it becomes industrially relevant to use such extractants in SIR-based extractions.
    Finally, in Chapter 6 the performed research is reviewed, and conclusions, recommendations and a wider perspective for future scientific challenges are given.

    Evaluation of tri-n-octylamine oxide as phenol extractant in a solvent impregnated resin
    Burghoff, B. ; Cuypers, R. ; Ettinger, M. van; Sudhölter, E.J.R. ; Zuilhof, H. ; Haan, A.B. de - \ 2009
    Separation and Purification Technology 67 (2009)1. - ISSN 1383-5866 - p. 117 - 120.
    aqueous-solutions - removal - water - acid
    Tri-n-ocytlamine oxide (TOAO) is evaluated as alternative to the state-of-the-art phenol extractants tri-n-octylphosphine oxide (TOPO) and Cyanex 923. Liquid¿liquid equilibrium experiments show that TOAO in 1,3-dimethylnaphthalene achieves higher phenol distribution coefficients in an extractant concentration range of 0.1¿1.25 mol L¿1 than respective TOPO/1,3-dimethylnaphthalene or Cyanex 923/1,3-dimethylnaphthalene solutions. In a solvent impregnated resin (SIR) application, the SIRs impregnated with TOAO/1,3-dimethylnaphthalene have a higher phenol capacity than the SIRs impregnated with Cyanex 923/1,3-dimethylnaphthalene. Regeneration of the SIRs with alkaline solution of pH 13 shows that both SIRs maintain a constant phenol capacity during at least seven cycles. Based on these observations TOAO can be considered as a better alternative to Cyanex 923
    Practical, reliable and inexpensive assay of lycopene in tomato products based on the combined use of light emitting diode (LED) and the optothermal window
    Bicanic, D.D. ; Cuypers, R. ; Luterotti, S. ; Sporec, M. ; Zoppi, A. ; Vugec, J. - \ 2008
    Acta Chimica Slovenica 55 (2008)2. - ISSN 1318-0207 - p. 468 - 473.
    performance liquid-chromatography - quantification - spectroscopy
    Light emitting diode (LED) combined with the concept of optothermal window (OW) is proposed as a new approach (LED-OW) to detect lycopene in a wide range of tomato-based products (tomato juice, tomato ketchup, tomato passata and tomato puree). Phytonutrient lycopene is a dominant antioxidant in these products while beta-carotene is present in significantly lower quantities. Therefore for all practical reasons the interfering effect of beta-carotene at 502 nm analytical wavelength can be neglected. The LED-OW method is low-cost and simple, yet accurate and precise. The major attributes of the new method are its rapid speed of response and the fact that no preparation whatsoever of the sample is needed before the analysis. The lycopene found in tomato products studied here varies from 8 mg/100 g to 60 mg/100 g fresh product. Results obtained by LED-OW method were compared to the outcome of conventional, time consuming spectrophotometric methods and the correlation was very good (R = 0.98). Precision of the LED-OW instrumental setup ranged from 0.5 to 7.4%; the RSD achieved for lycopene-richest samples (= 40 mg/100 g) did not exceed 1.7%. Repeatability of analysis by LED-OW was found to vary between 0.7 and 7.1%.
    Complexation of Phenols and Thiophenol by Phosphine Oxides and Phosphates. Extraction, Isothermal Titration Calorimetry, and ab Initio Calculations
    Cuypers, R. ; Burghoff, B. ; Marcelis, A.T.M. ; Sudhölter, E.J.R. ; Haan, A.B. de; Zuilhof, H. - \ 2008
    The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment, & General Theory 112 (2008)46. - ISSN 1089-5639 - p. 11714 - 11723.
    solvent-impregnated resins - hydrogen-bonded complexes - self-association - interaction energies - aqueous-solutions - water - acid - recovery - toluene - ion
    To develop a new solvent-impregnated resin system for the removal of phenols from water the complex formation of triisobutylphosphine sulfide (TIBPS), tributylphosphate (TBP), and tri-n-octylphosphine oxide (TOPO) with a series of phenols (phenol, thiophenol, 3-chlorophenol, 3,5-dichlorophenol, 4-cyanophenol, and pentachlorophenol) was studied. The investigation of complex formation between the extractants and the phenols in the solvent toluene was carried out using liquid¿liquid extraction, isothermal titration calorimetry (ITC), and quantum chemical modeling (B3LYP/6-311+G(d,p)//B3LYP/6-311G(d,p) and MP2/6-311++G(2d,2p)//B3LYP/6-311G(d,p)). The equilibrium constant (binding affinity, Kchem), enthalpy of complex formation (¿H), and stoichiometry (N) were directly measured with ITC, and the entropy of complexation (¿S) was derived from these results. A first screening of Kchem toward phenol revealed a very high binding affinity for TOPO, and very low binding affinities for the other extractants. Modeling results showed that although 1:1 complexes were formed, the TIBPS and TBP do not form strong hydrogen bonds. Therefore, in the remainder of the research only TOPO was considered. Kchem of TOPO for the phenols in toluene increased from 1¿000 to 10¿000 M¿1 in the order phenol
    Beslissen over bagger op bodem; deel 2 Onderbouwing stofgedragmodellering en voorspelde landbodemconcentraties na verspreiding bagger op land
    Noort, P. van; Cuypers, C. ; Wintersen, A. ; Zwart, D. de; Peijnenburg, J.G.M. ; Posthuma, L. ; Groenenberg, B.J. ; Harmsen, J. - \ 2006
    Bilthoven : RIVM (RIZA rapport 2006.001) - ISBN 9789036957090 - 69
    bodemchemie - bagger - toxicologie - uitspoelen - bodemwater - modellen - soil chemistry - dredgings - toxicology - soil water - leaching - models
    Dit rapport beschrijft een model voor het gedrag van toxische stoffen die in bodem gebracht worden door verspreiding van baggerspecie. Regelmatig baggeren is een noodzaak in Nederland. Verontreinigingen in de bagger zorgen daarbij voor een probleem. Waar moet de verontreinigde bagger heen? Momenteel wordt een verspreidingsbeleid gehanteerd dat gebaseerd is op verontreinigingsklassen. Dit systeem voldoet niet meer. In het kader van nieuw bodembeleid moet er anders naar dit probleem worden gekeken. Duurzaam gebruik van de bodem moet centraal staan, en gebiedsspecifiek beleid moet mogelijk worden. De bestaande klassenindeling geeft onvoldoende inzicht in lokale landbodemrisico¿s, en sluit niet aan bij het nieuwe beleid. In een onderzoek van RIVM, RIZA en Alterra is gekeken naar de risico¿s die op een lokatie door verspreiding op land kunnen ontstaan. Hiervoor is een systeembenadering opgesteld: waar komen de stoffen vandaan, waar gaan ze heen, welke organismen worden daadwerkelijk blootgesteld, en wat zijn de lokale risico¿s na verspreiding nu eigenlijk? Hiernaar wordt in drie samenhangende rapporten gekeken. In het voorliggende rapport wordt de systeembenadering technisch-wetenschappelijk beschreven. Hiermee kan beoordeeld worden of stoffen zich ophopen in de landbodem. In het opvolgende rapport wordt beschreven hoe de risico¿s van de stoffenmengsels voor mens, landbouwproducten en ecosystemen kunnen veranderen door het verspreiden van baggerspecie. In het overzichtsrapport van de serie wordt het op basis van de systeembenadering ontwikkelde beslismodel gepresenteerd, en worden de gevolgen van toepassing van het beslismodel verkend.
    Integrated risk assessment (IRA) helps to decide on land deposition of slightly contaminated sediments
    Posthuma, L. ; Cuypers, C. ; Noort, P. ; Harmsen, J. ; Zwart, D. de; Wintersen, A. - \ 2005
    In: Abstract book; SETAC Europe 15th Annual Meeting. - Brussels (Belgium) : SETAC Europe - p. 335 - 335.
    Non-symmetric banana-shaped liquid crystals with two different terminal alkoxy tails
    Achten, R. ; Cuypers, R. ; Giesbers, M. ; Koudijs, A. ; Marcelis, A.T.M. ; Sudhölter, E.J.R. - \ 2004
    Asymmetric banana-shaped liquid crystals with two different terminal alkoxy tails
    Achten, R. ; Cuypers, R. ; Giesbers, M. ; Koudijs, A. ; Marcelis, A.T.M. ; Sudhölter, E.J.R. - \ 2004
    Liquid Crystals 31 (2004)8. - ISSN 0267-8292 - p. 1167 - 1174.
    lateral substituents - mesophase behavior - distinct formation - achiral molecules - dimeric compounds - smectic phase - chirality - mesogens - field
    Two series of asymmetric banana-shaped compounds have been synthesized and studied. In the 1,3-phenylene bis[4-(4'-alkoxybenzoyloxy)]benzoate series the lack of symmetry was derived solely from the difference in length of the two terminal alkoxy chains. In the 3,4'-biphenylene bis[4-(4'-alkoxybenzoyloxy)]benzoate series the asymmetric nature originates from the 3,4'-substitution of the central biphenyl group and from the difference in length of the two terminal chains. All the melting points of the asymmetrical compounds in the series with the central phenyl unit are lower than those of the symmetrical compounds. The liquid crystalline B-1 or B-2 phase was retained in all cases. In the series with the central biphenyl unit the compounds with the shortest chain attached to the para -position of the central biphenyl unit have the lowest melting points. A significant lowering of the melting points in comparison with the symmetrically substituted compounds, however, could not be achieved. All the compounds of both series show a layer spacing which is comparable to those of the symmetrically substituted parent compounds. The observed switching behaviour of both the symmetric and asymmetric compounds with a B-2 phase was antiferroelectric.
    Modeling bioavailability of PAH in soil
    Rulkens, W.H. ; Bruning, H. ; Cuypers, M.P. - \ 2004
    In: Solid Waste: Assessment, monotoring and Remediation Elsevier - ISBN 9780080443218 - 1160 p.
    Bagger en bodem - een nieuw beslismodel voor verantwoorde toepassing van bagger op land
    Posthuma, L. ; Harmsen, J. ; Cuypers, M.P. ; Bladeren, C. van; Eijsden, G. van - \ 2003
    In: Bodem breed 2003; samenvattingen (voordrachten en en posters); 15e nationaal symposium bodembreed, 24 en 25 november 2003, congrescentrum de Werelt te Lunteren / van Mullekom, P., van Raay, L., Gouda : SKB-Duurzame Ontwikkeling Ondergrond - p. 150 - 151.
    Vergelijking van de inhalatie-anesthetica desfluraan, enfluraan, halotaan, isofluraan en sevofluraan
    Cuypers, R. ; Boer, K. de; Helden, Y.G.J. ; Smits, N.J.P. ; Stenger, R.M. ; Visser, G.M. ; Remie, R. - \ 2003
    Biotechniek 42 (2003)4. - ISSN 0166-6207 - p. 131 - 134.
    Quantifying bioavailability of PAHs in sediments using physical-chemical methods
    Rulkens, W.H. ; Cuypers, M.P. ; Grotenhuis, J.T.C. - \ 2002
    In: Proceedings of the First International Conference on Remediation of Contaminated Sediments - Characterization of Contaminated Sediments, Venice, Italy, 2001 / Pellei, M., Porta, A., Hinchee, R.E. (eds). - Columbus, Ohio, USA : Batelle Press, 2002. - ISBN 1-57477-127-2 - p. 279 - 286.
    Application of the PAH availability by rapid persulphate oxidation
    Grotenhuis, J.T.C. ; Cuypers, M.P. ; Pancras, T. - \ 2002
    In: Workshop 'Bioavailability of soil contaminants: problems and perspectives', Bremen, Germany, 2002 - p. 1 - 1.
    The estimation of PAH bioavailability in contaminated sediments using hydroxypropyl-ß-cyclodextrin and Trition X-100 extraction techniques
    Cuypers, M.P. ; Pancras, T. ; Grotenhuis, J.T.C. ; Rulkens, W.H. - \ 2002
    Chemosphere 46 (2002). - ISSN 0045-6535 - p. 1235 - 1245.
    Amorphous and condensed organic matter domains : the effects of persulfate oxidation on the composition of soil/sediment organic matter
    Cuypers, M.P. ; Grotenhuis, J.T.C. ; Nierop, K.G.J. ; Maneiro Franco, E. ; Jager, A. de; Rulkens, W.H. - \ 2002
    Chemosphere 48 (2002). - ISSN 0045-6535 - p. 919 - 931.
    The composition of amorphous and condensed soil/sediment organic matter (SOM) domains was investigated for one soil sample and four sediment samples. These samples were oxidized with persulfate to remove amorphous SOM, before and after which the composition of SOM was studied by thermogravimetric analysis, pyrolysis-GC/MS, and cross polarization magic angle spinning 13C-NMR. Comparison of the SOM composition before and after oxidation showed that condensed SOM was more thermostable and less polar than amorphous SOM. Condensed SOM was relatively low in O–alkyl C and carboxyl C and it was likely to contain only small amounts of labile organic components (carbohydrates, peptides, fatty acids). Apart from these general characteristics, the composition of the condensed and amorphous domains appeared to be highly dependent on the origin and nature of the SOM investigated. Condensed domains in relatively undecomposed SOM were enriched in aliphatic C, whereas condensed domains in relatively weathered SOM were enriched in aromatic C. Altogether, the compositional changes upon persulfate oxidation were similar to the compositional changes upon humification, which supports the idea that weathered SOM is more condensed than the original material.
    Quantifying bioavailability of PAHs in sediments using physical-chemical methods
    Rulkens, W.H. ; Cuypers, M.P. ; Grotenhuis, J.T.C. - \ 2001
    In: International Conference on Remediation of Contaminated Sites, Venice, Italy, 2001 - p. 1 - 1.
    Modeling Bioavailability of PAH in soil
    Rulkens, W.H. ; Bruning, H. ; Cuypers, M.P. ; Grotenhuis, J.T.C. - \ 2001
    In: Secotox World Congress and Sixth European Conference on Ecotoxicology and Environmental Safety. Ecotoxicology and Environmental Safety on the Verge of the Third Millenium: Trends, Threats and Challenges. Congress Proceedings, Krakow, Poland, 2001 / Twar, I., - p. 201 - 205.
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