67 research outputs found

    Scheiden van dieren = Weaning of animals

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    Separation of young animals from their parent(s) can cause welfare problems, if it occurs too early or in a wrong way. In this report we propose criteria for separation of young animals to prevent such problems and indicate for which species the current practice is a risk to cause welfare problems

    Photodynamic therapy: A promising new modality for the treatment of cancer

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    The first reports on photodynamic therapy (PDT) date back to the 1970s. Since then, several thousands of patients, both with early stage and advanced stage solid tumours, have been treated with PDT and many claims have been made regarding its efficacy. Nevertheless, the therapy has not yet found general acceptance by oncologists. Therefore it seems legitimate to ask whether PDT can still be described as "a promising new therapy in the treatment of cancer". Clinically, PDT has been mainly used for bladder cancer, lung cancer and in malignant diseases of the skin and upper aerodigestive tract. The sensitizer used in the photodynamic treatment of most patients is Photofrin, (Photofrin, the commercial name of dihematoporphyrin ether/ester, containing > 80% of the active porphyrin dimers/oligomers (A.M.R. Fisher, A.L. Murphee and C.J. Gomer, Clinical and preclinical photodynamictherapy, Review Series Article, Lasers Surg. Med., 17 (1995) 2-31). It is a complex mixture of porphyrins derived from hematoporphyrin. Although this sensitizer is effective, it is not the most suitable photosensitizer for PDT. Prolonged skin photosensitivity and the relatively low absorbance at 630 nm, a wavelength where tissue penetration of light is not optimal, have been frequently cited as negative aspects hindering general acceptance. A multitude of new sensitizers is currently under evaluation. Most of these "second generation photosensitizers" are chemically pure, absorb light at around 650 nm or greater and induce no or less general skin photosensitivity. Another novel approach is the photosensitization of neoplasms by the induction of endogenous photosensitizers through the application of 5-aminolevulinic acid (ALA). This article addresses the use of PDT in the disciplines mentioned above and attempts to indicate developments of PDT which could be necessary for this therapy to gain a wider acceptance in the various field

    A continuous-discontinuous model for crack branching

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    This is the peer reviewed version of the following article: Tamayo, E. [et al.]. A continuous-discontinuous model for crack branching. "International journal for numerical methods in engineering", 5 Octubre 2019, vol. 120, núm. 1, p. 86-104, which has been published in final form at https://doi.org/10.1002/nme.6125. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.A new continuous-discontinuous model for fracture that accounts for crack branching in a natural manner is presented. It combines a gradient-enhanced damage model based on nonlocal displacements to describe diffuse cracks and the extended finite element method (X-FEM) for sharp cracks. Its most distinct feature is a global crack tracking strategy based on the geometrical notion of medial axis: the sharp crack propagates following the direction dictated by the medial axis of a damage isoline. This means that, if the damage field branches, the medial axis automatically detects this bifurcation, and a branching sharp crack is thus easily obtained. In contrast to other existing models, no special crack-tip criteria are required to trigger branching. Complex crack patterns may also be described with this approach, since the X-FEM enrichment of the displacement field can be recursively applied by adding one extra term at each branching event. The proposed approach is also equipped with a crack-fluid pressure, a relevant feature in applications such as hydraulic fracturing or leakage-related events. The capabilities of the model to handle propagation and branching of cracks are illustrated by means of different two-dimensional numerical examples.Peer ReviewedPostprint (author's final draft

    Performance of four different diagnostic tests for C. difficile infection in piglets

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    Clostridium difficile is emerging as a pathogen in man as well as in animals. In 2000 it was described as a cause of neonatal enteritis in piglets and it is now the most common cause of neonatal diarrhoea in the USA. In Europe, C. difficile infection (CDI) in neonatal piglets has also been reported. Diagnosis of this infection is based on detection of the bacterium or its toxins A and B

    The occurrence of Pseudomonas aeruginosa in swimmingpoolwater with a temperature above 28 degree C

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    In 121 monsters zwemwater uit circulatiebaden met een watertemperatuur groter dan 28 graden C werd veertien maal Pseudomonas aeruginosa aangetroffen. Een ophopingsmethode met asparagine-bouillon gaf iets vaker positieve resultaten dan een ophopingsmethode met C-390 bouillon (twaalf maal) of een membraanfiltratiemethode met mPA-B agar (elf maal). De selectiviteit van de mPA-B methode was zeer goed, die van de ophopingsmethoden aanzienlijk minder. De aanwezigheid van P.aeruginosa ging met name gepaard met een laag gehalte aan vrij beschikbaar chloor en een verhoogde waarde van het koloniegetal bij 37 graden C. De bacterien werden met name aangetroffen in baden die niet voldeden aan het normenstelsel zoals dat is vastgelegd in het Besluit Hygiene en Veiligheid Zwemgelegenheden (1984).DGMH/DWB-
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