262 research outputs found

    In vivo pharmacokinetics of a gentamicin-loaded collagen sponge in acute periprosthetic infection - Serum values in 19 patients

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    Background The in vivo pharmacokinetics of gentamycin- loaded collagen fleeces in humans have not been described in the current literature. We therefore analyzed in vivo pharmacokinetics of these fleeces when used in the treatment of periprosthetic infections. Patients and methods Gentamycin concentrations were measured in 19 consecutive patients with an acute periprosthetic infection. Each patient received 2-5 fleeces (130 mg gentamycin/fleece). Results Initially, the blood concentration increased to 3.2-7.2 mg/L, depending on the number of fleeces that were applied. The serum peak concentrations resulted in peak/MIC ratios of 2.5-36 for P. aeruginosa, S. aureus, and Klebsiella spp. Subsequently, the serum values decreased almost linearly below 0.3 mg/L in 18 to 62 hours. After 24 hours, the serum levels of gentamicin dropped below 2 mg/L, the toxicity threshold. Interpretation The application of 2 to 5 130-mg gentamycin-loaded collagen fleeces may be useful as an adjuvant treatment for implant-related infections, since no toxic concentrations were measured 24 hours postoperatively

    Connectivity between migrating and landlocked populations of a diadromous fish species investigated using otolith microchemistry

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    Smelt Osmerus eperlanus has two different life history strategies in the Netherlands. The migrating population inhabits the Wadden Sea and spawns in freshwater areas. After the closure of the Afsluitdijk in 1932, part of the smelt population became landlocked. The fresh water smelt population has been in severe decline since 1990, and has strongly negatively impacted the numbers of piscivorous water birds relying on smelt as their main prey. The lakes that were formed after the dike closure, IJsselmeer and Markermeer have been assigned as Natura 2000 sites, based on their importance for (among others) piscivorous water birds. Because of the declining fresh water smelt population, the question arose whether this population is still supported by the diadromous population. Opportunities for exchange between fresh water and the sea are however limited to discharge sluices. The relationship between the diadromous and landlocked smelt population was analysed by means of otolith microchemistry. Our interpretation of otolith strontium (88Sr) patterns from smelt specimens collected in the fresh water area of Lake IJsselmeer and Markermeer, compared to those collected in the nearby marine environment, is that there is currently no evidence for a substantial contribution from the diadromous population to the spawning stock of the landlocked population

    Democratization and Social Movements: An Analysis of Elites and Masses in Democratic Transitions

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    Over the past several decades there has been an influx of countries becoming democracies. Post-communist Eastern Europe, developing Africa, and Latin America are only three regions that have been working towards democratic governments, some being more successful than others. There are many theories that attempt to explain why some countries are able to successfully transition to a democracy while others fail. In my senior thesis, I focus on elitism versus the power of the masses. For most of transitology history, elites have been viewed as the prominent actor in democratization. However, the role of the masses has been focused on more and more as time passes. I examine the histories and democratization processes in South Africa, Serbia, and Haiti, to determine the influence mass mobilization and elites have in democratic transitions. Mass mobilization is my independent variable, the variable that I am studying to see its impact, or lack of, on democratization processes in various countries. While the two theories do divulge prominent ideologies, I find that consensual elites and social movements are both not necessary for a democratic transition, but the democracy will most likely succeed in the long run if they are present. Therefore universalism is more supported for the transition process, while in order to consolidate there are certain preconditions that a country must reach first before attempting to democratize

    Herziening spieringadvisering

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    Het huidige spieringprotocol voor de openstelling van de visserij op spiering in het IJsselmeer en Markermeer-IJmeer dateert uit 1997 en is herzien in 2007. Het ministerie van LNV heeft aan WMR gevraagd om een advies over de herziening van het huidige afwegingskader (protocol). In 2013 is ook geprobeerd het protocol aan te passen, waarbij is geadviseerd om dit te doen door middel van een ecosysteemmodel (Osmose). Het model bleek niet uitvoerbaar omdat niet alle hiervoor benodigde gegevens en kennis aanwezig was. Om die reden is er nu een meer pragmatische en eenvoudiger aanpak toegepast

    Connectivity between Migrating and Landlocked Populations of a Diadromous fish Species Investigated Using Otolith Microchemistry

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    Smelt Osmerus eperlanus has two different life history strategies in the Netherlands. The migrating population inhabits the Wadden Sea and spawns in freshwater areas. After the closure of the Afsluitdijk in 1932, part of the smelt population became landlocked. The fresh water smelt population has been in severe decline since 1990, and has strongly negatively impacted the numbers of piscivorous water birds relying on smelt as their main prey. The lakes that were formed after the dike closure, IJsselmeer and Markermeer have been assigned as Natura 2000 sites, based on their importance for (among others) piscivorous water birds. Because of the declining fresh water smelt population, the question arose whether this population is still supported by the diadromous population. Opportunities for exchange between fresh water and the sea are however limited to discharge sluices. The relationship between the diadromous and landlocked smelt population was analysed by means of otolith microchemistry. Our interpretation of otolith strontium (88Sr) patterns from smelt specimens collected in the fresh water area of Lake IJsselmeer and Markermeer, compared to those collected in the nearby marine environment, is that there is currently no evidence for a substantial contribution from the diadromous population to the spawning stock of the landlocked population

    Poor accuracy of freehand cup positioning during total hip arthroplasty

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    Several studies have demonstrated a correlation between the acetabular cup position and the risk of dislocation, wear and range of motion after total hip arthroplasty. The present study was designed to evaluate the accuracy of the surgeon’s estimated position of the cup after freehand placement in total hip replacement. Peroperative estimated abduction and anteversion of 200 acetabular components (placed by three orthopaedic surgeons and nine residents) were compared with measured outcomes (according to Pradhan) on postoperative radiographs. Cups were placed in 49.7° (SD 6.7) of abduction and 16.0° (SD 8.1) of anteversion. Estimation of placement was 46.3° (SD 4.3) of abduction and 14.6° (SD 5.9) of anteversion. Of more interest is the fact that for the orthopaedic surgeons the mean inaccuracy of estimation was 4.1° (SD 3.9) for abduction and 5.2° (SD 4.5) for anteversion and for their residents this was respectively, 6.3° (SD 4.6) and 5.7° (SD 5.0). Significant differences were found between orthopaedic surgeons and residents for inaccuracy of estimation for abduction, not for anteversion. Body mass index, sex, (un)cemented fixation and surgical approach (anterolateral or posterolateral) were not significant factors. Based upon the inaccuracy of estimation, the group’s chance on future cup placement within Lewinnek’s safe zone (5–25° anteversion and 30–50° abduction) is 82.7 and 85.2% for anteversion and abduction separately. When both parameters are combined, the chance of accurate placement is only 70.5%. The chance of placement of the acetabular component within 5° of an intended position, for both abduction and anteversion is 21.5% this percentage decreases to just 2.9% when the tolerated error is 1°. There is a tendency to underestimate both abduction and anteversion. Orthopaedic surgeons are superior to their residents in estimating abduction of the acetabular component. The results of this study indicate that freehand placement of the acetabular component is not a reliable method

    Effects of climate variation on the breeding ecology of Arctic shorebirds

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    About 50 species of shorebirds breed in the Arctic, where they constitute the most characteristic component of the tundra avifauna. Here, we review the impact of weather and climate on the breeding cycle of shorebirds based on extensive studies conducted across the Arctic. Conditions for breeding shorebirds are highly variable among species, sites and regions, both within and between continents. Weather effects on breeding are most moderate in the Low Arctic of northern Europe and most extreme in the Siberian High Arctic. The decision of whether or not to breed upon arrival on the breeding grounds, the timing of egg-laying and the chick-growth period are most affected by annual variation in weather. In large parts of the Arctic, clutch initiation dates are highly correlated with snowmelt dates and in regions and years where extensive snowmelt occurs before or soon after the arrival of shorebirds, the decision to breed and clutch initiation dates appear to be a function of food availability for laying females. Once incubation is initiated, adult shorebirds appear fairly resilient to variations in temperature with nest abandonment primarily occurring in case of severe weather with new snow covering the ground. Feeding conditions for chicks, a factor highly influenced by weather, affects juvenile production in most regions. Predation has a very strong impact on breeding productivity throughout the Arctic and subarctic, with lemming Dicrostonyx spp. and Lemmus spp. fluctuations strongly influencing predation rates, particularly in the Siberian Arctic. The fate of Arctic shorebirds under projected future climate scenarios is uncertain, but High Arctic species and populations appear particularly at risk. Climatic amelioration may benefit Arctic shorebirds in the short term by increasing both survival and productivity, whereas in the long term habitat changes both on the breeding grounds and in the temperate and tropical non-breeding areas may put them under considerable pressure and may bring some of them near to extinction. Their relatively low genetic diversity, which is thought to be a consequence of survival through past climatically-driven population bottlenecks, may also put them more at risk to anthropogenic-induced climate variation than other avian taxa. &nbsp
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