Search

Item does not contain fulltext, BACKGROUND: Dried blood spot (DBS) sampling for pharmacokinetic (PK) studies and therapeutic drug monitoring have unique advantages over venous sampling. This study aimed to evaluate a DBS method for first-line anti-tuberculosis drugs in children, and DBS sampling to assess PK parameters. METHODS: Paraguayan children were treated according to the revised paediatric dosing scheme of the World Health Organization. A PK curve was performed both with DBS sampling and conventional venous sampling for rifampicin, pyrazinamide and ethambutol. Passing-Bablok regression, Bland-Altman plots and predictive performance evaluation were used to assess agreement between DBS and plasma concentrations. The percentages of patients attaining population PK values for Cmax and AUC0-24h were calculated. RESULTS: After use of a conversion factor, Passing-Bablok regression showed no significant proportional or systematic bias between DBS and plasma concentrations. Bland-Altman plots showed that 95% of the ratios of the DBS predicted:observed plasma concentrations lay between 0.6 and 1.4 for rifampicin, 0.5 and 1.6 for pyrazinamide and -0.4 and 2.8 for ethambutol. DBS measurements showed acceptable predictive performance for rifampicin and pyrazinamide, but not for ethambutol. Assessment of Cmax target attainment was 62.5% for isoniazid, 25% for rifampicin, 100% for pyrazinamide and 75% for ethambutol. CONCLUSION: For rifampicin and pyrazinamide, the DBS method was accurate in predicting plasma concentrations, and was used successfully for PK parameter assessment. However, predicting ethambutol plasma concentrations with DBS measurement was associated with too much imprecision. Despite higher dosing, only 25% of the population reached average target adult rifampicin exposures.

Contains fulltext : 188598.pdf (publisher's version ) (Open Access), Objectives: To improve information for patients and to facilitate a vaccination coverage that is in line with the EU and World Health Organization goals, we aimed to quantify how vaccination and patient characteristics impact on influenza vaccination uptake of elderly people. Methods: An online discrete choice experiment (DCE) was conducted among 1261 representatives of the Dutch general population aged 60 years or older. In the DCE, we used influenza vaccination scenarios based on five vaccination characteristics: effectiveness, risk of severe side effects, risk of mild side effects, protection duration, and absorption time. A heteroscedastic multinomial logit model was used, taking scale and preference heterogeneity (based on 19 patient characteristics) into account. Results: Vaccination and patient characteristics both contributed to explain influenza vaccination uptake. Assuming a base case respondent and a realistic vaccination scenario, the predicted uptake was 58%. One-way changes in vaccination characteristics and patient characteristics changed this uptake from 46% up to 61% and from 37% up to 95%, respectively. The strongest impact on vaccination uptake was whether the patient had been vaccinated last year, whether s/he had experienced vaccination side effects, and the patient’s general attitude towards vaccination. Conclusions: Although vaccination characteristics proved to influence influenza vaccination uptake, certain patient characteristics had an even higher impact on influenza vaccination uptake. Policy makers and general practitioners can use these insights to improve their communication plans and information regarding influenza vaccination for individuals aged 60 years or older. For instance, physicians should focus more on patients who had experienced side effects due to vaccination in the past, and policy makers should tailor the standard information folder to patients who had been vaccinated last year and to patient who had not.

Objectives: To improve information for patients and to facilitate a vaccination coverage that is in line with the EU and World Health Organization goals, we aimed to quantify how vaccination and patient characteristics impact on influenza vaccination uptake of elderly people. Methods: An online discrete choice experiment (DCE) was conducted among 1261 representatives of the Dutch general population aged 60 years or older. In the DCE, we used influenza vaccination scenarios based on five vaccination characteristics: effectiveness, risk of severe side effects, risk of mild side effects, protection duration, and absorption time. A heteroscedastic multinomial logit model was used, taking scale and preference heterogeneity (based on 19 patient characteristics) into account. Results: Vaccination and patient characteristics both contributed to explain influenza vaccination uptake. Assuming a base case respondent and a realistic vaccination scenario, the predicted uptake was 58%. One-way changes in vaccination characteristics and patient characteristics changed this uptake from 46% up to 61% and from 37% up to 95%, respectively. The strongest impact on vaccination uptake was whether the patient had been vaccinated last year, whether s/he had experienced vaccination side effects, and the patient's general attitude towards vaccination. Conclusions: Although vaccination characteristics proved to influence influenza vaccination uptake, certain patient characteristics had an even higher impact on influenza vaccination uptake. Policy makers and general practitioners can use these insights to improve their communication plans and information regarding influenza vaccination for individuals aged 60 years or older. For instance, physicians should focus more on patients who had experienced side effects due to vaccination in the past, and policy makers should tailor the standard information folder to patients who had been vaccinated last year and to patient who had not.

A key challenge in ecology is to understand how nutrients and light affect the biodiversity and community structure of phytoplankton and plant communities. According to resource competition models, ratios of limiting nutrients are major determinants of species composition. At high nutrient levels, however, species interactions may shift to competition for light, which might make nutrient ratios less relevant. The “nutrient‐load hypothesis” merges these two perspectives, by extending the classic model of competition for two nutrients to include competition for light. Here, we test five key predictions of the nutrient‐load hypothesis using multispecies competition experiments. A marine phytoplankton community sampled from the North Sea was inoculated in laboratory chemostats provided with different nitrogen (N) and phosphorus (P) loads to induce either single resource limitation or co‐limitation of N, P, and light. Four of the five predictions were validated by the experiments. In particular, different resource limitations favored the dominance of different species. Increasing nutrient loads caused changes in phytoplankton species composition, even if the N:P ratio of the nutrient loads remained constant, by shifting the species interactions from competition for nutrients to competition for light. In all treatments, small species became dominant whereas larger species were competitively excluded, supporting the common view that small cell size provides a competitive advantage under resource‐limited conditions. Contrary to expectation, all treatments led to coexistence of diatoms, cyanobacteria and green algae, resulting in a higher diversity of species than predicted by theory. Because the coexisting species comprised three phyla with different photosynthetic pigments, we speculate that niche differentiation in the light spectrum might play a role. Our results show that mechanistic resource competition models that integrate nutrient‐based and light‐based approaches pr

No abstract available

Contains fulltext : 174753.pdf (publisher's version ) (Open Access), BACKGROUND: The purpose of this study is to provide Dutch normative data and to assess internal consistency and known-groups validity for the TNO AZL Preschool Children Quality of Life (TAPQOL) and the acute version of the generic Pediatric Quality of Life Inventory (PedsQL 4.0) in Dutch young children aged 0-7 years. METHODS: Participants were selected from a panel of a large Dutch market research agency. A sample of 794 parents (response rate 61%, 39% fathers) of children (53% boys) from the general Dutch population, completed an electronic version of the TAPQOL (N = 227 infants aged 0-1 years) or PedsQL 4.0 (N = 293 toddlers aged 2-4 years and N = 274 young children aged 5-7 years). RESULTS: Except for the 'stomach' scale (alpha = .39), the TAPQOL showed acceptable to excellent internal consistency (alpha = .60-.88). The PedsQL 4.0 showed acceptable to excellent reliability in children aged 2-4 years (alpha = .60-.88) and in children aged 5-7 years (alpha = .76-.90). Children with a chronic health condition had lower scores than healthy children on 3 out of 12 domains of the TAPQOL (p = .001-.013) and on 2 out of 6 domains of the PedsQL 4.0 for children aged 2-4 years (p = .016-.04). The PedsQL 4.0 differentiated on all domains (p < .05) between children aged 5-7 years with and without a chronic health condition. CONCLUSION: In Dutch children aged 0-7 years old, HRQoL can be relialy measured with the TAPQOL and the PedsQL 4.0. However, it remains unclear whether these HRQoL instruments can distinguish between healthy children and children with a chronic health condition under the age of 5.

Dredging can have significant impacts on benthic marine organisms through mechanisms such as sedimentation and reduction in light availability as a result of increased suspension of sediments. Phototrophic marine organisms and those with limited mobility are particularly at risk from the effects of dredging. The potential impacts of dredging on benthic species depend on biological processes including feeding mechanism, mobility, life history characteristics (LHCs), stage of development and environmental conditions. Environmental windows (EWs) are a management technique in which dredging activities are permitted during specific periods throughout the year; avoiding periods of increased vulnerability for particular organisms in specific locations. In this review we identify these critical ecological processes for temperate and tropical marine benthic organisms; and examine if EWs could be used to mitigate dredging impacts using Western Australia (WA) as a case study. We examined LHCs for a range of marine taxa and identified, where possible, their vulnerability to dredging. Large gaps in knowledge exist for the timing of LHCs for major species of marine invertebrates, seagrasses and macroalgae, increasing uncertainty around their vulnerability to an increase in suspended sediments or light attenuation. We conclude that there is currently insufficient scientific basis to justify the adoption of generic EWs for dredging operations in WA for any group of organisms other than corals and possibly for temperate seagrasses. This is due to; 1) the temporal and spatial variation in the timing of known critical life history stages of different species; and 2) our current level of knowledge and understanding of the critical life history stages and characteristics for most taxa and for most areas being largely inadequate to justify any meaningful EW selection. As such, we suggest that EWs are only considered on a case-by-case basis to protect ecologically or economically importan

One of the major challenges in ecological stoichiometry is to establish howenvironmental changes in resource availability may affect both the biochemicalcomposition of organisms and the species composition of communities. This is apressing issue in many coastal waters, where anthropogenic activities have causedlarge changes in riverine nutrient inputs. Here we investigate variation in the biochemicalcomposition and synthesis of amino acids, fatty acids (FA), and carbohydrates inmixed phytoplankton communities sampled from the North Sea. The communities werecultured in chemostats supplied with different concentrations of dissolved inorganicnitrogen (DIN) and phosphorus (DIP) to establish four different types of resourcelimitations. Diatoms dominated under N-limited, NCP limited and P-limited conditions.Cyanobacteria became dominant in one of the N-limited chemostats and green algaedominated in the one P-limited chemostat and under light-limited conditions. Changesin nutrient availability directly affected amino acid content, which was lowest under Nand NCP limitation, higher under P-limitation and highest when light was the limitingfactor. Storage carbohydrate content showed the opposite trend and storage FAcontent seemed to be co-dependent on community composition. The synthesis ofessential amino acids was affected under N and NCP limitation, as the transformationfrom non-essential to essential amino acids decreased at DIN:DIP ? 6. The simplecommunity structure and clearly identifiable nutrient limitations confirm and clarifyprevious field findings in the North Sea. Our results show that different phytoplanktongroups are capable of adapting their key biosynthetic rates and hence their biochemicalcomposition to different degrees when experiencing shifts in nutrient availability. This willhave implications for phytoplankton growth, community structure, and the nutritionalquality of phytoplankton as food for higher trophic levels.

Item does not contain fulltext

Croplands play an important role in the carbon budget of many regions. However, the estimation of their carbon balance remains difficult due to diversity and complexity of the processes involved. We report the coupling of a one-dimensional soil water, heat, and CO2 flux model (SOILCO2), a pool concept of soil carbon turnover (RothC), and a crop growth module (SUCROS) to predict the net ecosystem exchange (NEE) of carbon. The coupled model, further referred to as AgroC, was extended with routines for managed grassland as well as for root exudation and root decay. In a first step, the coupled model was applied to two winter wheat sites and one upland grassland site in Germany. The model was calibrated based on soil water content, soil temperature, biometric, and soil respiration measurements for each site, and validated in terms of hourly NEE measured with the eddy covariance technique. The overall model performance of AgroC was sufficient with a model efficiency above 0.78 and a correlation coefficient above 0.91 for NEE. In a second step, AgroC was optimized with eddy covariance NEE measurements to examine the effect of different objective functions, constraints, and data-transformations on estimated NEE. It was found that NEE showed a distinct sensitivity to the choice of objective function and the inclusion of soil respiration data in the optimization process. In particular, both positive and negative day- and nighttime fluxes were found to be sensitive to the selected optimization strategy. Additional consideration of soil respiration measurements improved the simulation of small positive fluxes remarkably. Even though the model performance of the selected optimization strategies did not diverge substantially, the resulting cumulative NEE over simulation time period differed substantially. Therefore, it is concluded that data transformations, definitions of objective functions, and data sources have to be considered cautiously when a terrestrial ecosystem model i

Summary Marine Plants of the Perth Region will help readers to identify and learn about some of the many marine plants found in the Perth region. It includes information and full-colour pictures of a number of the many hundred species of flora that live in the waters of the Swan Coastal Plain. It is hoped that this guide will inspire you to delve further into the wonderful world of marine plants.