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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    Vitamin D, magnesium, calcium, and their interaction in relation to colorectal cancer recurrence and all-cause mortality
    Wesselink, Evertine ; Kok, Dieuwertje E. ; Bours, Martijn J.L. ; Wilt, Johannes H.W. De; Baar, Harm Van; Zutphen, Moniek Van; Geijsen, Anne M.J.R. ; Keulen, Eric T.P. ; Hansson, Bibi M.E. ; Ouweland, Jody Van Den; Witkamp, Renger F. ; Weijenberg, Matty P. ; Kampman, Ellen ; Duijnhoven, Fränzel J.B. Van - \ 2020
    American Journal of Clinical Nutrition 111 (2020)5. - ISSN 0002-9165 - p. 1007 - 1017.
    25(OH)D - all-cause mortality - calcium - colorectal cancer patients - interactions - magnesium - recurrence

    Background: Higher concentrations of 25-hydroxyvitamin D3 [25(OH)D3] at diagnosis are associated with a lower mortality risk in colorectal cancer (CRC) patients. However, magnesium and calcium are important in vitamin D metabolism. Objectives: We aimed to investigate 25(OH)D3, magnesium, or calcium and their interaction among patients with CRC in relation to recurrence and all-cause mortality. Methods: The study population included 1169 newly diagnosed stage I-III CRC patients from 2 prospective cohorts. Associations between 25(OH)D3 concentrations, magnesium or calcium intake through diet and/or supplements at diagnosis, and recurrence and all-cause mortality were evaluated using multivariable Cox proportional hazard models. The interaction between 25(OH)D3 and magnesium or calcium was assessed by investigating 1) joint compared with separate effects, using a single reference category; and 2) the effect estimates of 1 factor across strata of another. Results: Serum 25(OH)D3, calcium, and magnesium, alone and their interactions, were not associated with recurrence. Serum 25(OH)D3 concentrations seemed to be associated with all-cause mortality. An inverse association between magnesium intake (HRQ3 vs. Q1: 0.55; 95% CI: 0.32, 0.95 and HRQ4 vs. Q1: 0.65; 95% CI: 0.35, 1.21), but not calcium intake, and all-cause mortality was observed. When investigating the interaction between 25(OH)D3 and magnesium, we observed the lowest risk of all-cause mortality in patients with sufficient vitamin D concentrations (≥50 nmol/L) and a high magnesium intake (median split) (HR: 0.53; 95% CI: 0.31, 0.89) compared with patients who were vitamin D deficient (<50 nmol/L) and had a low magnesium intake. No interactions between calcium and vitamin D in relation to all-cause mortality were observed. Conclusions: Our findings suggest that the presence of an adequate status of 25(OH)D3 in combination with an adequate magnesium intake is essential in lowering the risk of mortality in CRC patients, yet the underlying mechanism should be studied. In addition, diet and lifestyle intervention studies are needed to confirm our findings. The COLON study was registered at clinicaltrials.gov as NCT03191110. The EnCoRe study was registered at trialregister.nl as NTR7099.

    Ternary Complex Formation of Phosphate with Ca and Mg Ions Binding to Ferrihydrite : Experiments and Mechanisms
    Mendez, Juan C. ; Hiemstra, Tjisse - \ 2020
    ACS Earth and Space Chemistry 4 (2020)4. - ISSN 2472-3452 - p. 545 - 557.
    anion-bridged complexes - calcium - CD model - cooperative and synergistic binding - electrostatic interactions - iron oxides nanoparticles - magnesium - surface complexation modeling

    Calcium (Ca) and magnesium (Mg) are the most abundant alkaline-earth metal ions in nature, and their interaction with ferrihydrite (Fh) affects the geochemical cycling of relevant ions, including phosphate (PO4). The interfacial interactions of Ca and Mg (M2+) with PO4 have not been analyzed yet for freshly precipitated Fh. Here, we studied experimentally this interaction in binary M2+-PO4 systems over a wide range of pH, M2+/PO4 ratios, and ion loadings. The primary adsorption data were scaled to the surface area of Fh using a recent ion-probing methodology that accounts for the size-dependent chemical composition of this nanomaterial (FeO1.4(OH)0.2·nH2O). The results have been interpreted with the charge distribution (CD) model, combined with a state-of-the-art structural surface model for Fh. The CD coefficients have been derived independently using MO/DFT/B3LYP/6-31+G*∗ optimized geometries. M2+ and PO4 mutually enhance their adsorption to Fh. This synergy results from the combined effect of ternary surface complex formation and increased electrostatic interactions. The type of ternary complex formed (anion- vs cation-bridged) depends on the relative binding affinities of the co-adsorbing ions. For our Ca-PO4 systems, modeling suggests the formation of two anion-bridged ternary complexes, i.e., (FeO)2PO2Ca and FeOPO3Ca. The latter is most prominently present, leading to a relative increase in the fraction of monodentate PO4 complexes. In Mg-PO4 systems, only the formation of the ternary FeOPO3Mg complex has been resolved. In the absence of Ca, the pH dependency of PO4 adsorption is stronger for Fh than for goethite, but this difference is largely, although not entirely, compensated in the presence of Ca. This study enables the use of Fh as a proxy for the natural oxide fraction, which will contribute to improved understanding of the mutual interactions of PO4 and M2+ in natural systems.

    The Use of Proton Pump Inhibitors May Increase Symptoms of Muscle Function Loss in Patients with Chronic Illnesses
    Vinke, Paulien ; Wesselink, Evertine ; Orten-Luiten, Wout van; Norren, Klaske van - \ 2020
    International Journal of Molecular Sciences 21 (2020)1. - ISSN 1661-6596
    cachexia - cancer - COPD - heart failure - inflammation - magnesium - microbiota - proton pump inhibitors - sarcopenic obesity - vitamin D

    Long-term use of proton pump inhibitors (PPIs) is common in patients with muscle wasting-related chronic diseases. We explored the hypothesis that the use of PPIs may contribute to a reduction in muscle mass and function in these patients. Literature indicates that a PPI-induced reduction in acidity of the gastrointestinal tract can decrease the absorption of, amongst others, magnesium. Low levels of magnesium are associated with impaired muscle function. This unwanted side-effect of PPIs on muscle function has been described in different disease backgrounds. Furthermore, magnesium is necessary for activation of vitamin D. Low vitamin D and magnesium levels together can lead to increased inflammation involved in muscle wasting. In addition, PPI use has been described to alter the microbiota's composition in the gut, which might lead to increased inflammation. However, PPIs are often provided together with nonsteroidal anti-inflammatory drugs (NSAIDs), which are anti-inflammatory. In the presence of obesity, additional mechanisms could further contribute to muscle alterations. In conclusion, use of PPIs has been reported to contribute to muscle function loss. Whether this will add to the risk factor for development of muscle function loss in patients with chronic disease needs further investigation.

    Bieten bijbemesten na opkomst
    Verstegen, Harry - \ 2015
    arable farming - sugarbeet - sugar content - fertilizer application - crop growth stage - boron fertilizers - boron - manganese - deficiency diseases - magnesium
    Relationships between soil fertility, herbage quality and manure composition on grassland-based dairy farms
    Reijneveld, J.A. ; Abbink, G.W. ; Termorshuizen, A.J. ; Oenema, O. - \ 2014
    European Journal of Agronomy 56 (2014). - ISSN 1161-0301 - p. 9 - 18.
    new-zealand - agricultural land - phosphorus status - central-europe - new-york - yield - management - magnesium - trends - fertilization
    It is reasonable to expect that compliance with grassland fertilization recommendations in the long run results in optimal soil fertility, and subsequent herbage quality. Here, we evaluate the development of soil, herbage and manure characteristics and their relation over the last decades. We hypothesized that herbage and manure quality are related with soil fertility. We used a large database with results of soil tests, spring forage quality characteristics, and manure analyses, which were made on demand of dairy farmers. We considered the Netherlands as a whole and three selected regions with contrasting soil types (sandy soil, riverine clay, and peaty marine clay). Effects of soil fertility on herbage quality were evident when comparing farms. Farms higher in soil P and K generally have correspondingly higher contents in forage. On average, soil fertility and herbage characteristics were within or just above the agronomical optimal range during the last decades. Herbage crude protein content decreased in all regions during last two decades, which is likely an effect of legislative measures on decreasing the application of N. Selenium (Se) and sulphur (S) contents increased sharply on sandy soils, likely because of increased use of Se and S containing fertilizers. Manure composition did not differ between soil types. In conclusion, at farm level, the element composition of herbage reflected the soil fertility status. The contents of S, P, K, Na, Mg, and Ca in the herbage were all significantly influenced by soil fertility characteristics. Our results emphasize the importance of maintaining soil fertility for high quality roughage production. (C) 2014 Elsevier B.V. All rights reserved.
    Evaluation of using spot urine to replace 24 h urine sodium and potassium excretions
    Hooft Van Huysduynen, E.J.C. ; Hulshof, P.J.M. ; Lee, L. van; Geelen, A. ; Feskens, E.J.M. ; Veer, P. van 't; Woerkum, C.M.J. van; Vries, J.H.M. de - \ 2014
    Public Health Nutrition 17 (2014)11. - ISSN 1368-9800 - p. 2505 - 2511.
    24-hour - collections - completeness - creatinine - magnesium - calcium - samples - marker - acid
    Objective The most accurate method to estimate Na and K intakes is to determine 24 h urinary excretions of these minerals. However, collecting 24 h urine is burdensome. Therefore it was studied whether spot urine could be used to replace 24 h urine samples. Design Participants collected 24 h urine and kept one voiding sample separate. Na, K and creatinine concentrations were analysed in both 24 h and spot urine samples. Also 24 h excretions of Na and K were predicted from spot urine concentrations using the Tanaka and Danish methods. Setting In 2011 and 2012, urine samples were collected and brought to the study centre at Wageningen University, the Netherlands. Subjects Women (n 147) aged 19–26 years. Results According to p-aminobenzoic acid excretions, 127 urine collections were complete. Correlations of Na:creatinine, K:creatinine and Na:K between spot urine and 24 h urine were 0·68, 0·57 and 0·64, respectively. Mean 24 h Na excretion predicted with the Tanaka method was higher (difference 21·2 mmol/d, P
    Variation in phosphorus content of milk from dairy cattle as affected by differences in milk composition
    Klop, G. ; Ellis, J.L. ; Blok, M.C. ; Brandsma, G.G. ; Bannink, A. ; Dijkstra, J. - \ 2014
    The Journal of Agricultural Science 152 (2014)5. - ISSN 0021-8596 - p. 860 - 869.
    environmental-impact - methane production - blood-plasma - beef-cattle - cows - excretion - prediction - magnesium - calcium
    In view of environmental concerns with regard to phosphorus (P) pollution and the expected global P scarcity, there is increasing interest in improving P utilization in dairy cattle. In high-producing dairy cows, P requirements for milk production comprise a significant fraction of total dietary P requirements. Although variation in P content of milk can affect the efficiency of P utilization for milk production (i.e. the fraction of ingested P that is incorporated in milk), this variation is poorly understood. It was hypothesized that the P content of milk is related to both milk protein and milk lactose content, but not necessarily to milk fat content. Three existing experiments comprising individual animal data on milk yield and fat, protein, lactose and P content of milk (in total 278 observations from 121 cows) were analysed to evaluate this hypothesis using a mixed model analysis. The models including the effects of both protein and lactose content of milk yielded better prediction of milk P content in terms of root-mean-square prediction error (RMSPE) and concordance correlation coefficient (CCC) statistics than models with only protein included as prediction variable; however, estimates of effect sizes varied between studies. The inclusion of milk fat content in equations already including protein and lactose did not further improve prediction of milk P content. Equations developed to describe the relationship between milk protein and lactose contents (g/kg) and milk P content (g/kg) were: (Expt 1) P in milk=-0·44(±0·179)+0·0253(±0·00300)×milk protein+0·0133(±0·00382)×milk lactose (RMSPE: 5·2%; CCC: 0·71); (Expt 2) P in milk=-0·26 (±0·347)+0·0174(±0·00328)×milk protein+0·0143 (±0·00611)×milk lactose (RMSPE: 6·3%; CCC: 0·40); and (Expt 3) P in milk=-0·36(±0·255)+0·0131(±0·00230)×milk protein+0·0193(±0·00490)×milk lactose (RMSPE: 6·5%; CCC: 0·55). Analysis of the three experiments combined, treating study as a random effect, resulted in the following equation to describe the same relationship as in the individual study equations: P in milk=-0·64(±0·168)+0·0223(±0·00236)×milk protein+0·0191(±0·00316)×milk lactose (RMSPE: 6·2%; CCC: 0·61). Although significant relationships between milk protein, milk lactose and milk P were found, a considerable portion of the observed variation remained unexplained, implying that factors other than milk composition may affect the P content of milk. The equations developed may be used to replace current fixed milk P contents assumed in P requirement systems for cattle.
    Electrochemical phosphate recovery from nanofiltration concentrates
    Kappel, C. ; Yasadi, K. ; Temmink, B.G. ; Metz, S.J. ; Kemperman, A.J.B. ; Nijmeijer, K. ; Zwijnenburg, A. ; Witkamp, G.J. ; Rijnaarts, H. - \ 2013
    Separation and Purification Technology 120 (2013). - ISSN 1383-5866 - p. 437 - 444.
    amorphous calcium-phosphate - municipal waste-water - aqueous-solution - precipitation - hydroxyapatite - magnesium - struvite - removal - substitution - experiences
    The high total phosphorus content of raw domestic wastewater with its significant eutrophication potential offers an excellent possibility for phosphate recovery. Continuous recirculation of NF concentrate to an MBR and simultaneous phosphate recovery from the NF concentrate can be applied to produce reusable water, recovering phosphates, while at the same time decreasing the scaling potential of the recirculated NF concentrate, prolonging the retention times of slowly biodegradable soluble compounds (e.g. micropollutants) and recirculating multivalent cations to promote the bio-flocculation. Here we introduce an electrochemical system to recover phosphates. An electrochemical cell was divided into an anode and a cathode compartment separated by a cation exchange membrane. Precipitation of phosphates from nanofiltration concentrate was induced by locally increasing the pH at the cathode surface by water electrolysis and thereby creating supersaturated conditions at the cathode. 70–95% recovery of total phosphate was achieved at a pH of 8–10 near the cathode. Ion analysis, XRD and ATR-FTIR spectra indicated that the precipitate consisted of amorphous calcium phosphate (ACP) and minor proportions of amorphous calcium carbonate (ACC). The amount of ACC was dependent on the pH. Calcium phosphate scaling at the cathode surface did not occur due to H2-gas formation preventing nucleation and growth at the cathode.
    An attempt to define the sodium requirements of lactating dairy cows in a tropical environment
    Thiangtum, W. ; Yawongsa, A. ; Schonewille, J.T. ; Rukkwamsuk, T. ; Yuangklang, C. ; Verstegen, M.W.A. ; Hendriks, W.H. - \ 2011
    Journal of the Science of Food and Agriculture 91 (2011)13. - ISSN 0022-5142 - p. 2333 - 2337.
    acid-base status - potassium-chloride - mineral metabolism - dietary-sodium - heat-stress - responses - supplementation - magnesium - bicarbonate - absorption
    BACKGROUND: Lactating dairy cattle in the tropics may require more sodium (Na) owing to the hot and humid climatic conditions. It is unknown whether the current recommendations on Na for lactating cows can be quantitatively used in tropical countries. This study attempted to define the Na requirement of lactating dairy cows under tropical conditions by measuring Na levels in saliva, milk and faeces. RESULTS: The concentrations of Na and potassium (K) in milk, faeces and serum were not affected by dietary treatments. The amount of Na absorbed by cows fed the basal (low-Na) diet containing 0.4 g Na kg-1 dry matter (DM) was equal to the amount of Na lost in the milk, showing that these animals were fed an Na-deficient ration. This observation was corroborated by salivary Na and K levels, with the cows on the low-Na diet having salivary Na concentrations below 120 mmol L-1 in combination with salivary K concentrations above 20 mmol L-1 (P <0.05). CONCLUSION: Consumption of a daily ration formulated to contain the current Na requirement set by the NRC appears to provide too much Na for lactating cows under tropical conditions. A tentative value of 1.2 g kg-1 DM is proposed as the Na requirement for dairy cows under tropical conditions. Copyright © 2011 Society of Chemical Industry
    Serum micronutrient concentrations and childhood asthma: the PIAMA birth cohort study
    Oeffelen, A.A.M. van; Bekkers, M.B.M. ; Smit, H.A. ; Kerkhof, M. van de; Koppelman, G.H. ; Haveman-Nies, A. ; A, D.L. van der; Jansen, E.H.J.M. ; Wijga, A.H. - \ 2011
    Pediatric Allergy and Immunology 22 (2011)8. - ISSN 0905-6157 - p. 784 - 793.
    nutrition examination survey - vitamin-d levels - zinc status - trace-elements - t-lymphocytes - smooth-muscle - children - magnesium - selenium - cells
    Background: Research suggests an influence of micronutrients on childhood asthma. So far, evidence mainly originates from cross-sectional studies using nutrient intake data, which is not an accurate measure of nutrient status. This study aimed to investigate the cross-sectional and prospective associations between serum concentrations of magnesium, vitamin D, selenium, and zinc and prevalence of (severe) asthma, atopy, and bronchial hyperresponsiveness (BHR) in childhood. Methods: In the Prevention and Incidence of Asthma and Mite Allergy birth cohort study, serum nutrient concentrations were available for a 4-yr-old subgroup (n = 372) and for a different 8-yr-old subgroup (n = 328). Yearly questionnaires inquired about asthma prevalence until 8 yr of age. Allergic sensitization was measured at 4 and 8 yr of age; BHR was measured at 8 yr of age. Data were analyzed with logistic regression and generalized estimating equations models. Results: There was a consistent (non-significant) inverse association between serum magnesium concentrations and asthma prevalence. Serum vitamin D concentrations measured at age 4 were inversely associated with asthma at ages 4–8 [e.g., cross-sectional association between vitamin D tertile 3 vs. 1 and severe asthma: odds ratio (OR): 0.49, 95% confidence interval (CI): 0.25–0.95], whereas vitamin D measured at age 8 was positively associated with asthma at age 8 (e.g., cross-sectional association between vitamin D tertile 3 vs. 1 and severe asthma: OR: 2.14, 95% CI: 0.67–6.82). Conclusions: Our study contributes to the evidence that children with higher serum magnesium concentrations are less likely to have asthma. The associations between serum vitamin D concentrations and asthma were age-dependent
    Bladvlekken in lelie door gebrek of overmaat aan elementen tijdens winterbroei : bemesting tijdens de broei van lelie, tweede proef
    Slootweg, G. ; Kok, B.J. ; Aanholt, J.T.M. van - \ 2010
    Lisse : PPO Bloembollen en Bomen - 30
    lilium - lelies - forceren van planten - voedingsstoffenopname (planten) - magnesium - calcium - sulfaat - fosfor - kalium - landbouwkundig onderzoek - nederland - lilium - lilies - forcing - nutrient uptake - magnesium - calcium - sulfate - phosphorus - potassium - agricultural research - netherlands
    Tekort en overmaat van een aantal elementen tijdens de leliebroei, hebben ook in dit onderzoek (in de winter) bladproblemen laten zien. Van de specifieke effecten was de bladschade door magnesiumgebrek het grootst. Calciumgebrek gaf de bekende bladverbranding. Van gebrek of overmaat aan mangaan, sulfaat, fosfor en kalium zijn geen bladproblemen gezien. Stikstofgebrek uitte zich in een lichte bladkleur en lichte takken bij de oogst. Er kwamen bij op vrij grote schaal bruine bladvlekken voor, die niet aan een enkel element waren toe te schrijven. Een overmaat van Mn, Ca, SO4, P en K voorkwam het optreden van deze bladvlekken volledig. Er was bij veel elementen weinig effect van een tekort te zien, hoewel de elementen in het substraat volledig afwezig waren. Van een aantal elementen was de voorraad in de bol kennelijk weer voldoende om grote problemen door gebrek te voorkomen. De resultaten komen overeen met de proef in de zomer van 2009.
    Urinary calcium excretion in non-lactating dairy cows in relation to intake of fat-coated rice bran
    Martin-Tereso, J. ; Derks, M. ; Laar, H. van; Mulder, K. ; Hartog, L.A. den; Verstegen, M.W.A. - \ 2010
    Journal of Animal Physiology and Animal Nutrition 94 (2010)1. - ISSN 0931-2439 - p. 129 - 136.
    cation-anion difference - milk fever - dry period - gastrointestinal-tract - parturient paresis - hypocalcemia - absorption - magnesium - supplementation - phosphorus
    At calving, many older cows fail to compensate the sudden demand of calcium by an adequate activation of intestinal absorption. This results in a variable degree of hypocalcaemia. Reducing intestinal availability of calcium during the close-up period can prevent milk fever. Fat-coated rice bran (FCRB) was investigated for its potential to reduce Ca availability in pre-calving cows. Fat-coated rice bran was incubated in situ to estimate ruminal degradation of dry matter and phytic acid. Also, seven dry multiparous dairy cows were used for a feeding trial in three periods of approximately 1 week each: P1: adaptation; P2: feeding of 2 kg of FCRB and P3: withdrawal of FCRB. Feed intake was recorded and daily urine samples were analysed for pH, Ca and creatinine. The bypass fraction of phytic acid (passage rate: 5%/h) was 30%. Fat-coated rice bran depressed dry matter intake in P2, resulting in a lower Ca intake. In P2 urine pH and calcium excretion were lower. Daily calcium excretion decreased after introduction of FCRB, peaked after withdrawal and dropped 2 days later. Changes in urinary Ca excretion by feeding FCRB indicate that FCRB affected Ca homeostasis in dry multiparous dairy cows
    Fosfaatonderzoek Powerstart in zaaiuien 2008 : op kleigrond
    Paauw, J.G.M. - \ 2009
    Lelystad : Praktijkonderzoek Plant & Omgeving, Business Unit Akkerbouw, Groene Ruimte en Vollegrondsgroenten - 12
    allium cepa - uien - mengmeststoffen - fosfaten - magnesium - kalium - zink - opbrengsten - bemesting - allium cepa - onions - compound fertilizers - phosphates - magnesium - potassium - zinc - yields - fertilizer application
    In dit rapport staat het resultaat van een onderzoek naar de fosfaatwerking van Powertstart in het gewas zaaiuien. Powerstart is een vloeibare meststof die de mineralen fosfaat, kalium, magnesium en zink bevat. De meststof is tijdens het zaaien toegediend.
    Sleutelen aan bladproblemen bij lelie
    Slootweg, G. ; Kok, B.J. ; Aanholt, J.T.M. van - \ 2009
    Vakblad voor de Bloemisterij 64 (2009)51. - ISSN 0042-2223 - p. 38 - 39.
    lelies - bladvlekkenziekte - magnesium - calcium - plantenvoeding - kunstmeststoffen - lilies - leaf spotting - plant nutrition - fertilizers
    Leliebroeiers constateren jaarrond bladvlekken in hun gewas die zijn niet kunnen verklaren. In de zomer van 2009 heeft PPO in Lisse bij vier cultivars bekeken of de oorzaak ligt in gebrek of overmaat van voedingselementen. Er moet vooral voldoende magnesium zijn. Met calcium kan een teler problemen voorkomen.
    Effects of dietary protein and energy levels on cow manure extretion and ammonia votalization
    Stelt, B. van der; Vliet, P.C.J. van; Reijs, J.W. ; Temminghoff, E.J.M. ; Riemsdijk, W.H. van - \ 2008
    Journal of Dairy Science 91 (2008)12. - ISSN 0022-0302 - p. 4811 - 4821.
    lactating dairy-cows - nitrogen - emissions - cattle - slurry - manipulation - prediction - management - magnesium - digestion
    Adjusting dietary composition is considered an effective way to reduce nutrient losses to the environment. The effects of various dietary protein and energy levels on manure composition (Ca, Mg, K, Na, N, P, and pH) were studied by determining total and direct available (free) nutrient concentrations in 8 slurries obtained from a feeding trial. Furthermore, the effects of dietary changes on NH3 volatilization from manure slurries were studied. Increasing the crude protein (CP) content of the feed (108 to 190 g/ kg of dry matter) resulted in an average increase in total N and P content of the slurries of 56 and 48%, respectively. Feeding the cows more energy (5,050 to 6,840 kJ/kg of dry matter) increased total N and P content of the slurries by 27 and 39%, respectively. Total ammoniacal nitrogen (TAN) amounted to 52 to 77% of the total N content present in manure slurries. A low protein content or a low energy content of the diets reduced TAN concentrations in the slurries by 43% (CP) or 25% (energy). Changes in the protein content or the energy content of the feed did not significantly affect the free:total ratios of Na, Ca, and Mg content of the slurries. In agreement with the calculated NH3,aq (aqueous) content, the total amount of NH3 volatilized from manure slurries was much greater (on average 10 times greater) when the cows were fed greater levels of CP. Although the slurries contained more TAN when cows were fed diets richer in energy, NH3 volatilization from the slurries was lower.
    Zonder magnesium zouden planten niet groen zijn
    Heuvelink, E. ; Kierkels, T. - \ 2007
    Onder Glas 4 (2007)9. - p. 40 - 41.
    chlorofyl - plantenfysiologie - plantenontwikkeling - magnesium - fysiologische functies - gewassen, groeifasen - voedingsstoffenbehoeften - glastuinbouw - chlorophyll - plant physiology - plant development - magnesium - physiological functions - crop growth stage - nutrient requirements - greenhouse horticulture
    Magnesium is het centrale element in het molecuul van het bladgroen. Bij een gebrek kleuren daarom de bladeren geel tussen de nerven. Zware metalen kunnen de plaats van magnesium in het bladgroen innemen. De plant kan dan niet meer assimileren. Magnesium is verder belangrijk bij heel veel processen in de plant
    Toenail cerium levels and risk of a first acute myocardial infarction: The EURAMIC and heavy metals study
    Gomez-Aracena, J. ; Riemersma, R.A. ; Veer, P. van 't; Kok, F.J. - \ 2006
    Chemosphere 64 (2006)1. - ISSN 0045-6535 - p. 112 - 120.
    neutron-activation analysis - endomyocardial fibrosis - adipose-tissue - european men - pneumoconiosis - antioxidants - association - fibroblasts - lanthanides - magnesium
    The association between cerium status and risk of first acute myocardial infarction (AMI) was examined in a case-control study in 10 centres from Europe and Israel. Cerium in toenails was assessed by neutron activation analysis in 684 cases and 724 controls aged 70years or younger. Mean concentrations of cerium were 186 and 173mug/kg in cases and controls, respectively. Cerium was positively associated with low socio-economic status, smoking, mercury, zinc and scandium (p0.001). Cases had significantly higher levels of cerium than controls after adjustment for age and centre (case-control ratio 1.074; 95% CI 1.002-1.151) and increased in further adjustment for other cardiovascular risk factors 1.085; 95% CI 1.025-1.149. The risk after adjustment for age and centre was higher with increasing cerium levels (p for trend=0.02). After adjustment for BMI, history of hypertension, smoking, alcohol intake, diabetes, family history of CHD, beta-carotene, lycopene, alpha-tocopherol, selenium, mercury and scandium, the OR for the highest quintile was 1.43 (95% CI 0.85-2.41; p-trend 0.08). When we applied this same model in non-smokers the odds ratios in the 4th and 5th quintiles of cerium as compared with the lowest were 2.09 (95% CI 1.05-4.16) and 2.81 (95% CI 1.21-6.52), respectively, p-trend 0.011. Our results suggest that toenail cerium levels may be associated with an increased risk of AMI, but more research is warranted to shed further light and fully understand the plausibility and public health implications of these findings.
    Optimalisering van de magnesiumvoorziening van aardappelen
    Paauw, J.G.M. - \ 2005
    Kennisakker.nl 2003 (2005)15 feb.
    solanum tuberosum - aardappelen - rassen (planten) - magnesium - spuiten - toedieningswijzen - gewasopbrengst - gewaskwaliteit - gebrek - bemesting - akkerbouw - potatoes - varieties - spraying - application methods - crop yield - crop quality - shortage - fertilizer application - arable farming
    In veel aardappelrassen komt magnesiumgebrek voor. Er wordt vaak een magnesiumbespuiting geadviseerd, zonder dat er sprake is van magnesiumgebrek. In de praktijk zijn er veel onduidelijkheden over het nut van magnesium. Daartoe is er, in opdracht van HPA, in 2003 en 2004 bemestingsonderzoek uitgevoerd om te zien of magnesium een positief effect heeft op de opbrengst en kwaliteit. Daarnaast is gekeken naar de rasgevoeligheid voor magnesium, welke magnesiummeststof het best werkt en of er grondsoorteffecten zijn. Op basis van de resultaten van dit onderzoek blijft het oude advies actueel: spuiten zodra er onder in het gewas magnesiumgebrek is waargenomen. Niet spuiten kan dan opbrengstderving veroorzaken. Spuiten zonder dat er zichtbaar magnesiumgebrek is, geeft geen opbrengstverhoging.
    Aluminium concentration versus the base cation to aluminium ratio as predictors for aluminium toxicity in Pinus sylvestris and Picea abies seedlings
    Schöll, L. van; Keltjens, W.G. ; Hoffland, E. ; Breemen, N. van - \ 2004
    Forest Ecology and Management 195 (2004)3. - ISSN 0378-1127 - p. 301 - 309.
    norway spruce seedlings - gleditsia-triacanthos l - critical loads - root-growth - forest soils - calcium - magnesium - plants - inhibition - resistance
    Aluminium (Al) toxicity is considered an important factor in forest deterioration caused by soil acidification. A ratio of base cations (BC) to Al in the soil solution lower than 1 is widely used as an indicator for potentially adverse effects on tree health. In our view, the validity of the assumptions underlying the use of the BC:AI ratio as an indicator for Al toxicity in trees has never been evaluated properly. Here, we evaluate the importance of the base cations Ca and Mg in counteracting Al toxicity. Pinus sylvestris and Picea abies seedlings were grown on nutrient solution with a range of Al (0-0.25-0.5-1-2 mM) and base cation (0.25-0.5-2 mM) concentrations, giving BC:Al ratios of 1 at different levels of Al. Increasing concentrations of Al in solution caused growth reductions, which could not be counteracted by increasing concentrations of BC in solution with P. sylvestris and only partly counteracted with P. abies. Increased concentrations of Al in solution decreased the concentrations in shoot and root of both Ca and Mg, while increased concentrations of BC in solution increased tissue concentrations of BC. Growth reductions were, however, not a result of BC deficiencies, as growth reduction already occurred in tree seedlings that maintained adequate concentrations of Ca and Mg. All growth and uptake variables measured showed a higher or equal correlation with the absolute concentrations of Al or Al + BC in solution than with the BC:Al ratio. We conclude that Al toxicity is determined solely by the concentration of Al in solution. Shoot growth decreased significantly as dissolved Al increased at a constant BC:Al ratio of 1. In P. abies, but not in P. sylvestris, dissolved BC can positively affect uptake of BC and growth, which might partly alleviate the toxic effects of Al. Our results show that the mechanistic explanation for the effect of the BC:Al ratio is insufficient to describe Al toxicity. Care should be taken when using models based on the BC:AI ratio to predict the effect of Al on tree growth. (C) 2004 Elsevier B.V. All rights reserved.
    Myocardial infarction risk in relation to zinc concentration in toenails
    Martin-Moreno, J.M. ; Gorgojo, L. ; Riemersma, R.A. ; Gomez-Aracena, J. ; Kark, J.D. ; Guillen, J. ; Jimenez, J. ; Ringstad, J.J. ; Fernandez-Crehuet, J. ; Bode, P. ; Kok, F.J. - \ 2003
    The British journal of nutrition 89 (2003)5. - ISSN 0007-1145 - p. 673 - 678.
    coronary heart-disease - trace-elements - cardiovascular-disease - serum copper - magnesium - calcium - nutrition - selenium - tissue - cancer
    Zn is an essential mineral. The role of Zn in atherosclerosis is not clear. Epidemiological studies, which have reported contradictory results, are limited by the use of serum Zn levels as a marker of intake. We assessed the association of toenail Zn, which integrates dietary Zn intake over 3 to 12 months, with the risk of a first myocardial infarction. Toenail Zn concentrations were determined by neutron activation analysis in the European multi-centre case–control study on antioxidants, myocardial infarction and breast cancer. This multi-centre case–control study included 684 cases and 724 controls from eight European countries and Israel. Toenail Zn levels of controls (adjusted for age and study centre) were positively associated with age, a-tocopherol and Se, but not with additional dietary variables or with classical risk factors for CHD. Average toenail Zn was 106·0 mg/kg in cases (95 % CI 103·1, 108·9) and 107·5 mg/kg in controls (95 % CI 104·5, 110·7). After controlling for cardiovascular risk factors and for centre, the adjusted odds ratios of myocardial infarction for quintiles 2–5 of toenail Zn with respect to the first quintile were 0·97 (95 % CI 0·59, 1·58), 1·15 (95 % CI 0·72, 1·85), 0·91 (95 % CI 0·56, 1·50), and 0·85 (95 % CI 0·52, 1·39). The P for trend was 0·45. In conclusion toenail Zn levels (reflecting long-term dietary intake) were not significantly associated with acute myocardial infarction.
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