New type of vulnerability curve gives insight in the hydraulic capacitance and conductivity of the xylem

Drought vulnerability of trees and other woody plants is much debated in the context of climate change, which creates a high interest in understanding plant water relations. The role and functioning of internal water storage is crucial, but still insufficiently understood. Drought vulnerability is typically assessed by considering loss in conductivity in function of decreasing xylem water potential, in a so-called ‘vulnerability curve’. The xylem water potential at which a certain percentage of conductivity is lost (usually 50%) gives an indication of the vulnerability to cavitation. In a ‘desorption curve’, we can examine the release of water from internal storage tissues with decreasing water potential. Both curves are very valuable, but rely on a sequence of manual measurements (xylem water potential, hydraulic conductivity and water content) and are time-consuming. Therefore, we propose a new type of vulnerability curve that is based on continuous measurements of diameter shrinkage and ultrasonic acoustic emissions (UAE). We monitored weight loss, xylem diameter shrinkage and UAE and measured xylem water potential during the dehydration of excised branches of Vitis vinifera L. ‘Johanniter’. The vulnerability curves could be interpreted in terms of water loss in elastic and inelastic tissues. The proposed method can be a tool to assess hydraulic capacitance and conductivity of the xylem

Evaluation of medication adherence methods in the treatment of malaria in Rwandan infants

Objectives: To compare three methods for evaluating treatment adherence in a 7-day controlled treatment period for malaria in children in Rwanda. Methods: Fifty-six children (< 5 years) with malaria were recruited at the University Hospital of Butare, Rwanda. Patients were treated with quinine sulfate, taste-masked, pellets during seven days: three days in hospital (in-patient) followed by a four-day out-patient period. Three methods to evaluate medication adherence among patients were compared: manual pill count of returned tablets, patient self-report and electronic pill-box monitoring. These pill-boxes were equipped with a microchip registering date and time of every opening. Medication adherence was defined as the proportion of prescribed doses taken. The inter-dose intervals were analysed as well. Results: Medication adherence data were available for 54 of the 56 patients. Manual pill count and patient self-report yielded a medication adherence of 100% for the in-and out-patient treatment periods. Based on electronic pill-box monitoring, medication adherence during the seven-day treatment period was 90.5 +/- 8.3%. Based on electronic pillbox monitoring inpatient medication adherence (99.3 +/- 2.7%) was markedly higher (p < 0.03) than out-patient adherence (82.7 +/- 14.7%), showing a clear difference between health workers' and consumers' medication adherence. Conclusion: Health workers' medication adherence was good. However, a significant lower medication adherence was observed for consumers' adherence in the outpatient setting. This was only detected by electronic pill-box monitoring. Therefore, this latter method is more accurate than the two other methods used in this study

Different effects of tocolytic medication on blood pressure and blood pressure amplification

Background The importance of tocolysis has been discussed extensively. Beta-2 adrenoceptor agonistic drugs like ritodrine have been the reference tocolytic drugs in most countries. Cardiovascular side-effects are frequent. Atosiban, a newer tocolytic drug, is a competitive antagonist of oxytocin and has fewer cardiovascular side effects. Although large studies exist, there is mainly subjective reporting of adverse reactions with a focus on blood pressure data. Objectives Evaluation of the acute effects of therapeutic doses of ritodrine and atosiban in comparison to placebo on central and peripheral blood pressures, central-to-peripheral blood pressure amplification and the augmentation index (AIx) in healthy non-pregnant female volunteers. Methods A double-blind, randomized, crossover trial was carried out in 20 healthy non-pregnant female volunteers. Hemodynamic measurements were performed under standardized conditions. Results At steady state, central and peripheral pressures did not differ from placebo in the atosiban group. During ritodrine-infusion, central SBP increased by 11% versus placebo (p = 0.012) and peripheral SBP by 10% (p = 0.004). In contrast to atosiban and placebo, blood pressure amplification was absent in the ritodrine group. While the AIx did not change in the atosiban group, with ritodrine, the AIx tended to decrease. Conclusions The present study shows the significant effects of ritodrine on the cardiovascular system. Atosiban has no significant effects and may be an appropriate alternative to tocolyticum, particularly in cardiovascularly complicated pregnancies

Development of Uranium Reference Particles to Support Nuclear Safeguards

Controlled hydrolysis of certified uranium hexafluoride, carried out in a specifically constructed aerosol chamber, leads to the production of uranyl fluoride particulates which ¿deposited on a graphite planchet support ¿ may be used as a quality control reference material. The particle size and surface distribution depends on several parameters, such as relative humidity inside the aerosol chamber and the concentration of gaseous uranium hexafluoride, determined by the distillation conditions. The best quality samples were obtained a RH ranging from 55 to 70% and low gas amount. These improvements for a single deposition were used to prepare a reference sample with two different uranium enrichments. Preliminary SIMS measurements proved good results with respect to both type of particles. It was also revealed that ¿ in some case ¿ the micrometer size uranium particles are accompanied by a large medium background.JRC.DG.D.2-Reference material