A comparison of UVb compact lamps in enabling cutaneous vitamin D synthesis in growing bearded dragons          下载免费PDF全文

J. J. E. Diehl  F. M. Baines  A. C. Heijboer  J. P. van Leeuwen  M. Kik  W. H. Hendriks  D. G. A. B. Oonincx 《Journal of animal physiology and animal nutrition》2018,102(1):308-316

The effect of exposure to different UVb compact lamps on the vitamin D status of growing bearded dragons (Pogona vitticeps) was studied. Forty‐two newly hatched bearded dragons (<24 h old) were allocated to six treatment groups (n = 7 per group). Five groups were exposed to different UVb compact lamps for two hours per day, with a control group not exposed to UVb radiation. At 120 days of age, blood samples were obtained and concentrations of 25(OH)D₃, Ca, P and uric acid were determined. In addition, plasma 25(OH)D₃ concentration was determined in free‐living adult bearded dragons to provide a reference level. Only one treatment resulted in elevated levels of 25(OH)D₃ compared to the control group (41.0 ± 12.85 vs. 2.0 ± 0.0 nmol/L). All UVb‐exposed groups had low 25(OH)D₃ plasma levels compared to earlier studies on captive bearded dragons as well as in comparison with the free‐living adult bearded dragons (409 ± 56 nmol/L). Spectral analysis indicated that all treatment lamps emitted UVb wavelengths effective for some cutaneous vitamin D synthesis. None of these lamps, under this regime, appeared to have provided a sufficient UVb dose to enable synthesis of plasma 25(OH)D₃ levels similar to those of free‐living bearded dragons in their native habitat.  相似文献   

Hypoglycin A Concentrations in Maple Tree Species in the Netherlands and the Occurrence of Atypical Myopathy in Horses          下载免费PDF全文

C.M. Westermann  R. van Leeuwen  L.W.D. van Raamsdonk  H.G.J. Mol 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2016,30(3):880-884

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‘Universal’ spray droplet adhesion model – accounting for hairy leaves     

J J Nairn  W A Forster  R M van Leeuwen 《Weed Research》2013,53(6):407-417

The adhesion of a spray droplet upon initial contact with a leaf surface is extremely important to spray efficacy and is dependent on dynamic interactions between droplets (formulation, size, velocity) and leaf (micro‐topography, surface chemistry, veininess, hairiness and orientation). A ‘universal’ spray droplet adhesion model has previously been developed, using 50% aqueous acetone contact angles as a measure of leaf surface properties; this model satisfactorily predicts initial adhesion over a range of formulation surface tensions, droplet sizes and velocities. However, it failed to fit data from hairier leaves. This study investigates initial spray droplet adhesion on hairy leaves. Two categories of hairy leaves were identified by how the droplets penetrate the leaf hairs, Wenzel (hairy) and Cassie–Baxter (super hairy). For the Wenzel‐type, a simple constant accounted for the increased droplet shatter caused by the hairs. For the Cassie–Baxter‐type, a cushioning factor was introduced to account for the absorption of kinetic energy at impact by the hair mat. The cushioning factor was estimated by measuring the relative height of the hair mat. By including these two parameters, the new model successfully predicted the mean adhesion of non‐hairy, hairy and super‐hairy plants (R² = 0.96). This model and the underlying principles determining hairy leaf adhesion developed in this article will help develop spray formulations effective at targeting hairy‐leaved weed and crop species.  相似文献   

Evaluating the efficacy of potential fungicide-adjuvant combinations for control of myrtle rust in New Zealand     

Adusei-Fosu  Kwasi  Rolando  Carol A.  Richardson  Brian  van Leeuwen  Rebecca  Gaskin  Robyn  Bader  Martin K.-F.  Pathan  Amin K. 《植物病害和植物保护杂志》2021,128(6):1501-1515

Journal of Plant Diseases and Protection - Myrtle rust is a serious fungal disease caused by Austropuccinia psidii affecting a number of Myrtaceae species in New Zealand and elsewhere. Control with...  相似文献   

Prediction of sweet pepper (<Emphasis Type="Italic">Capsicum annuum</Emphasis>) flavor over different harvests     

P. M. Eggink  C. Maliepaard  Y. Tikunov  J. P. W. Haanstra  L. M. M. Pohu-Flament  S. C. de Wit-Maljaars  F. Willeboordse-Vos  S. Bos  C. Benning-de Waard  P. J. de Grauw-van Leeuwen  G. Freymark  A. G. Bovy  R. G. F. Visser 《Euphytica》2012,187(1):117-131

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Kinetic study of the activation process of a latent mushroom (Agaricus bisporus) tyrosinase by serine proteases.   总被引：2，自引：0，他引：2  

J C Espín  J van Leeuwen  H J Wichers 《Journal of agricultural and food chemistry》1999,47(9):3509-3517

Latent mushroom tyrosinase can be considered as a zymogen when activated by proteases because the activation process fulfilled all of the kinetic dependencies predicted by a theoretical zymogen activation model previously reported. The activation was studied under two assay conditions: high and low ratio of latent tyrosinase/serine protease (trypsin and subtilisin Carlsberg) concentrations, in the presence and in the absence of a serine protease inhibitor (aprotinin). The size of the latent enzyme was 67 kDa, determined by denaturing SDS-PAGE electrophoresis and Western blot assays. After proteolytic activation, the size was 43 kDa, with an intermediate band of 58 kDa. The values of the catalytic () and Michaelis () constants for the active forms of tyrosinase resulting from the activation by subtilisin, trypsin, or sodium dodecyl sulfate on the substrate tert-butylcatechol were slightly different, which could support the idea of "one activator-one different active tyrosinase". Vacuum infiltration experiments tried to reproduce in vivo the role of mushroom serine proteases in the activation of latent tyrosinase. The use of serine protease inhibitors is proposed as a new alternative tool to prevent melanin formation.  相似文献   

1H NMR and chemometrics to characterize mature grape berries in four wine-growing areas in Bordeaux, France   总被引：1，自引：0，他引：1  

Pereira GE  Gaudillere JP  Van Leeuwen C  Hilbert G  Lavialle O  Maucourt M  Deborde C  Moing A  Rolin D 《Journal of agricultural and food chemistry》2005,53(16):6382-6389

The biochemical composition of grape berries depends on the cultivar genome and is influenced by environmental conditions and growing practices, which vary according to origin and "terroir" (French word accounting for the factors of climate, soil, and cultural practices on grape and wine quality). The components currently measured to determine the potential quality of grapes for wine-making at harvest are sugars, acidity, pH, and total phenolics, referred to as "classic analysis". The aim of this work was to establish metabolic profiles using both conventional physicochemical analyses and 1H NMR spectrometry of the skin and pulp of mature berry extracts in order in four appellations situated in different locations in southern-western France (Bordeaux). Principal component analysis was applied to the physiochemical and 1H NMR data to investigate the variability of the grape composition and to characterize groups of samples. A significant clustering of the metabolic profile of pulps or skins in relation to their terroir was observed. Physicochemical analyses were more discriminant than 1H NMR data, but NMR spectroscopy allowed metabolic finger-printings using identified metabolites and some still nonattributed resonances.  相似文献   

An eccentric binary millisecond pulsar in the galactic plane     

Champion DJ  Ransom SM  Lazarus P  Camilo F  Bassa C  Kaspi VM  Nice DJ  Freire PC  Stairs IH  van Leeuwen J  Stappers BW  Cordes JM  Hessels JW  Lorimer DR  Arzoumanian Z  Backer DC  Bhat ND  Chatterjee S  Cognard I  Deneva JS  Faucher-Giguère CA  Gaensler BM  Han J  Jenet FA  Kasian L  Kondratiev VI  Kramer M  Lazio J  McLaughlin MA  Venkataraman A  Vlemmings W 《Science (New York, N.Y.)》2008,320(5881):1309-1312

Binary pulsar systems are superb probes of stellar and binary evolution and the physics of extreme environments. In a survey with the Arecibo telescope, we have found PSR J1903+0327, a radio pulsar with a rotational period of 2.15 milliseconds in a highly eccentric (e = 0.44) 95-day orbit around a solar mass (M(middle dot in circle)) companion. Infrared observations identify a possible main-sequence companion star. Conventional binary stellar evolution models predict neither large orbital eccentricities nor main-sequence companions around millisecond pulsars. Alternative formation scenarios involve recycling a neutron star in a globular cluster, then ejecting it into the Galactic disk, or membership in a hierarchical triple system. A relativistic analysis of timing observations of the pulsar finds its mass to be 1.74 +/- 0.04 M solar symbol, an unusually high value.  相似文献   

Norovirus outbreak in a natural playground: A One Health approach     

Gregorius J. Sips  Mariëlle J. G. Dirven  Joke T. Donkervoort  Francien M. van Kolfschoten  Claudia M. E. Schapendonk  My V. T. Phan  Annemieke Bloem  Anna F. van Leeuwen  Mariechristine E. Trompenaars  Marion P. G. Koopmans  Annemiek A. van der Eijk  Miranda de Graaf  Ewout B. Fanoy 《Zoonoses and public health》2020,67(4):453-459

Norovirus constitutes the most frequently identified infectious cause of disease outbreaks associated with untreated recreational water. When investigating outbreaks related to surface water, a One Health approach is insightful. Historically, there has been a focus on potential contamination of recreational water by bird droppings and a recent publication demonstrating human noroviruses in bird faeces suggested this should be investigated in future water‐related norovirus outbreaks. Here, we describe a One Health approach investigating a norovirus outbreak in a natural playground. On social media, a large amount of waterfowl were reported to defecate near these playground premises leading to speculations about their potential involvement. Surface water, as well as human and bird faecal specimens, was tested for human noroviruses. Norovirus was found to be the most likely cause of the outbreak but there was no evidence for transmission via waterfowl. Cases had become known on social media prior to notification to the public health service underscoring the potential of online media as an early warning system. In view of known risk factors, advice was given for future outbreak investigations and natural playground design.  相似文献   

The effect of different postweaning altrenogest treatments of primiparous sows on follicular development, pregnancy rates, and litter sizes     

van Leeuwen JJ  Williams SI  Martens MR  Jourquin J  Driancourt MA  Kemp B  Soede NM 《Journal of animal science》2011,89(2):397-403

This study investigated follicular development during and after postweaning altrenogest treatment of primiparous sows in relation to subsequent reproductive performance. Primiparous sows (n = 259) were randomly assigned at weaning (d 0) to 1 of 4 groups: control (no altrenogest, n = 71), RU4 (20 mg of altrenogest from d -1 to 2, n = 62), RU8 (20 mg of altrenogest from d -1 to 6, n = 65), or RU15 (20 mg of altrenogest from d -1 to 13, n = 61). Average follicular size (measured by ultrasound) increased during altrenogest treatment and resulted in larger follicles at the start of the follicular phase for RU4, RU8, and RU15 compared with controls (5.3 ± 0.9, 5.5 ± 1.3, 5.1 ± 1.2, and 3.4 ± 0.6 mm, respectively; P < 0.0001). Farrowing rate was greater in RU15 (95%) than in RU8 (76%; P = 0.04). The RU15 group also had more piglets (2 to 3 more piglets total born and born alive; P < 0.05) than the other treatment groups. Follicular development at weaning clearly affected reproductive performance. At weaning, average follicular size: small (<3.5 mm), medium (3.5 to 4.5 mm), or large (≥ 4.5 mm), was associated with farrowing rates of 86, 78, and 48%, respectively (P < 0.001). Sows with large follicles at weaning had low farrowing rates (71%) in RU4, very low farrowing rates (22%) in RU8, but normal farrowing rates in RU15 (83%). In conclusion, this study showed that 15 d of postweaning altrenogest treatment of primiparous sows may allow follicle turnover in sows that had large follicles at weaning and that this was associated with an improved reproductive performance. It also showed that shorter treatment with altrenogest (4 or 8 d) is beneficial for sows with small follicles at weaning, but is not recommendable for sows with large follicles at weaning.  相似文献