150 research outputs found
Quantitative Computerized Assessment of the Degree of Acetabular Bone Deficiency: Total radial Acetabular Bone Loss (TrABL)
A novel quantitative, computerized, and, therefore, highly objective method is presented to assess the degree of total radical acetabular bone loss. The method, which is abbreviated to “TrABL”, makes use of advanced 3D CT-based image processing and effective 3D anatomical reconstruction methodology. The output data consist of a ratio and a graph, which can both be used for direct comparison between specimens. A first dataset of twelve highly deficient hemipelves, mainly Paprosky types IIIB, is used as illustration. Although generalization of the findings will require further investigation on a larger population, it can be assumed that the presented method has the potential to facilitate the preoperative use of existing classifications and related decision schemes for treatment selection in complex revision cases
Bepaling van totaal kwik en kwikspecies in milieu- en biologische monsters
Kwik behoort tot de meest toxische metalen. Het neemt een unieke plaats in omwille van zijn chemische en fysische eigenschappen. Vermits kwik bij kamer-temperatuur vooral in gasvormige fase voorkomt, zal het zich snel via de atmosfeer verspreiden in hydro-, bio- en lithosfeer. Door zijn relatief inerte vorm kan het over lange afstanden getransporteerd te worden en dient het beschouwd te worden als een globale polluent. De toxiciteit van kwik hangt af van de chemische vorm waarin het voorkomt. Zo zijn organokwikverbindingen veel toxischer dan anorganisch kwik. Methylkwik, dat voornamelijk gevormd wordt in aquatisch milieu door biotische en abiotische processen, wordt geaccumuleerd in vis, waardoor het in de voedselketen terecht komt. Daardoor is het heel belangrijk om een onderscheid te kunnen maken tussen de verschillende species. In een eerste luik van dit werk werd voor de bepaling van kwik in omgevingslucht een manuele bemonsterings- en analysemethode op punt gesteld en 2 commercieel verkrijgbare semi-automatische monitoren geëvalueerd, waarna veldtesten werden uitgevoerd in Vlaanderen. Dit werk werd uitgevoerd ter voorbereiding van de uitbouw van een kwikimmissiemeetnet in Vlaanderen, in opdracht van de Vlaamse Milieumaatschappij. In een tweede luik werden de mogelijkheden nagegaan van elektro-thermische vervluchtiging inductief gekoppeld plasma massaspectrometrie (ETV-ICPMS) voor de bepaling van totaal kwik en kwikspecies in biologische monsters. Deze methode laat de directe bepaling toe vanuit vaste monsters, waardoor uitgebreide monstervoorbereidingen, die gepaard kunnen gaan met contaminatie, verliezen en/of speciestransformatie, vermeden worden. Hiertoe werd een zelfgemaakte gasvormige isotopisch aangerijkte Hg-standaard gegenereerd en isotopendilutie als kalibratiemethode toegepast, wat in die combinatie een vernieuwende aanpak was. Er werden vis-, haar-, slib- en sedimentmonsters geanalyseerd
Frondoside A suppressive effects on lung cancer survival, tumor growth, angiogenesis, invasion, and metastasis
A major challenge for oncologists and pharmacologists is to develop less toxic drugs that will improve the survival of lung cancer patients. Frondoside A is a triterpenoid glycoside isolated from the sea cucumber, Cucumaria frondosa and was shown to be a highly safe compound. We investigated the impact of Frondoside A on survival, migration and invasion in vitro, and on tumor growth, metastasis and angiogenesis in vivo alone and in combination with cisplatin. Frondoside A caused concentration-dependent reduction in viability of LNM35, A549, NCI-H460-Luc2, MDA-MB-435, MCF-7, and HepG2 over 24 hours through a caspase 3/7-dependent cell death pathway. The IC50 concentrations (producing half-maximal inhibition) at 24 h were between 1.7 and 2.5 mu M of Frondoside A. In addition, Frondoside A induced a time- and concentration-dependent inhibition of cell migration, invasion and angiogenesis in vitro. Frondoside A (0.01 and 1 mg/kg/day i.p. for 25 days) significantly decreased the growth, the angiogenesis and lymph node metastasis of LNM35 tumor xenografts in athymic mice, without obvious toxic side-effects. Frondoside A (0.1-0.5 mu M) also significantly prevented basal and bFGF induced angiogenesis in the CAM angiogenesis assay. Moreover, Frondoside A enhanced the inhibition of lung tumor growth induced by the chemotherapeutic agent cisplatin. These findings identify Frondoside A as a promising novel therapeutic agent for lung cancer
The effect of partial depopulation on Campylobacter introduction in broiler houses
Poultry is seen as the main reservoir for Campylobacter. Control of this zoonotic pathogen in primary production could potentially reduce the colonization in broiler flocks and consequently reduce the number of human infections. In the present study, 20 broiler flocks from 10 farms, were sampled immediately before and 5 to 7 d after partial depopulation (thinning) for the presence of Campylobacter using cecal droppings and overshoes. At the time of thinning, the catching crew, transportation vehicles, forklift, and transport containers were sampled for the presence of Campylobacter. Samples were cultivated; presumed positive isolates were confirmed by PCR. The isolates were molecularly typed by flaA restriction analysis and pulsed field gel electrophoresis. Results show that all flocks were thinned using Campylobacter-contaminated equipment and materials. One-third of the broiler flocks became colonized after thinning. In 67% of the colonization cases, identical strains were found matching those of container systems, transport trucks, and/or forklifts. This identifies thinning as an important risk factor for Campylobacter introduction into broiler houses. Setup and compliance with biosecurity practices during thinning is essential to prevent Campylobacter colonization of broiler flocks
Contamination Sources and Transmission Routes for Campylobacter on (Mixed) Broiler Farms in Belgium, and Comparison of the Gut Microbiota of Flocks Colonized and Uncolonized with Campylobacter
Biosecurity seems to be the most promising tool for Campylobacter control on poultry farms. A longitudinal molecular epidemiological study was performed during two production cycles, in which the broilers, the poultry house, and the environment of 10 (mixed) broiler farms were monitored weekly. Cecal droppings from the second production cycle were also used for 16S metabarcoding to study the differences in the microbiota of colonized and uncolonized flocks. Results showed that 3 out of 10 farms were positive for Campylobacter in the first production cycle, and 4 out of 10 were positive in the second. Broilers became colonized at the earliest when they were four weeks old. The majority of the flocks (57%) became colonized after partial depopulation. Before colonization of the flocks, Campylobacter was rarely detected in the environment, but it was frequently isolated from cattle and swine. Although these animals appeared to be consistent carriers of Campylobacter, molecular typing revealed that they were not the source of flock colonization. In accordance with previous reports, this study suggests that partial depopulation appears to be an important risk factor for Campylobacter introduction into the broiler house. Metabarcoding indicated that two Campylobacter-free flocks carried high relative abundances of Megamonas in their ceca, suggesting potential competition with Campylobacter
Mechanistic modelling of a fatty acid distillation plant : iterative approach for component lumping and industrial validation
Onderzoek naar de trekvissoorten in het Schelde-estuarium. Voortplantings-en opgroeihabitat van rivierprik en fint
Migratory fish such as river lamprey and twaite shad are important indicators of ecosystem functioning. Over the past century, most migratory fish have disappeared from the river Scheldt due to human impacts. The previous study on migratory fishes in the Scheldt showed however that most species show the first signs of recovery (Stevens et al., 2009). For both river lamprey and twaite shad there are strong indications that they reproduce in the Scheldt. However, the spawning and nursery habitats of both species are unknown and it is unclear whether the preconditions for a sustainable recovery are met. The spawning and nursery habitat of river lamprey can be located through targeted sampling of the larvae in the sediment. Sampling with fyke nets showed that adult river lamprey migrate mainly to the Bovenschelde and Zwalmbeek. In both rivers a number of locations were selected, which are, according to the literature, expected to be suitable habitats for the larvae of river lamprey. Wadable sites were sampled with a specially designed sediment pump and the deeper sites with a Van Veen grab. In neither of these rivers, however, river lamprey larvae could be found and no spawning sites could be identified. Possible reasons for the lack of larvae in the samples are (1) that no suitable larval habitat is present in the studied areas, (2) that the larval density in the investigated habitats is low and hence sampling frequency should be increased, (3) that the River Bovenschelde and the River Zwalm are not the main spawning grounds for river lamprey in the Scheldt. Telemetry of adult river lamprey could be a possible solution to locate the spawning grounds. In order to improve the reproduction and survival of river lamprey in the River Bovenschelde, the migration barriers in the Scheldt and its tributaries should be cleared and sufficient larval habitat should be availability. Larval habitat could be created in the River Zwalm and other tributaries through the restoration of natural banks. In addition, mud and sand banks in the Bovenschelde should be protected as much as possible as potential larval habitat.The population of twaite shad in the Scheldt is too small to identify the critical habitats by sampling in the field. Therefore, a habitat suitability model for spawning and larval shad was constructed based on literature data. Hereto, we first selected the environmental variables that determine habitat suitability. Next, for each variable the tolerance range was determined. Finallly, the variables were combined using fuzzy logic in order to determine the degree of suitability of a habitat. The model predicts the presence of suitable spawning habitat in the Upper Zeeschelde, upstream of the River Durme. Later in the season, when the water temperature rises, suitable spawning habitat is also present in the Rivers Kleine Nete and Grote Nete. Suitable habitat for larval shad is located mainly in the Upper Zeeschelde upstream Rupelmonde and in the River Rupel. Spawning of twaite shad takes place in the main channel and during their ontogeny the larvae migrate to the edges of the main channel and to side channels.Therefore, in areas with suitable spawning and larval habitat, both the main and side channels need protection. In particular mudflats, sand flats and subtidal low dynamic habitats should be safeguarded. Dredging of these habitats thus mortgages the recovery of the twaite shad population in the Scheldt. The oxygen concentration in the estuary has been greatly improved in recent years.However, in summer a low-oxygen zone in the freshwater area persists, comprising the upstream migration of adults and the survival of larvae. Periodic hypoxic conditions should therefore be avoided and a minimum oxygen content of 5 mg / l is essential for both adults and larvae. During the last century, hydrodynamics in the estuary has increased markedly. As a result, larvae have more difficulties in maintaining their position in suitable habitat. Actions that increase the river/tidal flow or eliminate local retention areas should therefore be avoided
Evaluatie van vismigratie in de Demer in Diest. Evaluatie van de Grote Steunbeer als potentieel knelpunt en de Zwarte Beek als alternatieve route voor vismigratie
- …