Characterization of the erosive power of the suspension used within the framework of accelerated wear tests of spraying nozzles.

The study concerns the application techniques of agrochemical products and especially focuses on the wear of spraying nozzles. This one leads to a modification of the spraying characteristics and the homogeneity of distribution deteriorates. An accelerated wear process of nozzles is defined by the standard ISO 5682-1, which makes it possible to compare the wear resistance of the different nozzles available on the market. In order to accelerate the process, an erosive suspension is used in the test rig, but this suspension looses its characteristics during the utilisation time. This is the reason why a system measuring continuously the erosive power has been set up. This system is validated by different discontinuous measurement and the correlation observed have a coefficient of about 0,99. From the signal detected by the new device, two calculations have been carried out. A first one determining continuously the total wear quantity of the nozzles. A second one identifying continuously the erosive power of the suspension. On the one hand, we obtain a basis allowing to compare the wear resistance of nozzles and on the other hand, a parameter indicating the appropriate time to change the suspension

Season-dependent physiological behavior of Miscanthus x giganteus growing on heavy-metal contaminated areas in relation to soil properties

Miscanthus x giganteus is often considered as a suitable plant species for phytomanagement of heavy metal polluted sites. Nevertheless, its physiological behavior in response to the level of metal toxicity throughout the growing season remains poorly documented. Miscanthus x giganteus was cultivated on three sites in Belgium (BSJ: non-polluted control; CAR: slightly contaminated; VM strongly polluted by Cd, Pb, Cu, Zn, Ni and As). The presence of Miscanthus improved soil biological parameters assessed by measurement of enzyme activity and basal soil respiration on the three considered sites, although to a lower level on VM site. Heavy metal accumulation in the shoot was already recorded in spring. It displayed a contrasting distribution in the summer leaves since heavy metals and As metalloid accumulated mainly in the older leaves of CAR plants while showing a uniform distribution among leaves of different ages in VM plants. Comparatively to plants growing on BSJ, net photosynthesis decreased in plants growing on CAR and VM sites. The recorded decrease was mainly related to stomatal factors in CAR plants (decrease in stomatal conductance and in Ci) but to non-stomatal factors such as decrease in carboxylation efficiency and non-photochemical quenching in VM plants. Stomata remained open in VM plants which presented lower instantaneous and intrinsic water use efficiencies than CAR and BSJ plants. High proportions of heavy metals accumulated in CAR plants were bound to the cell wall fraction while the soluble and organelle-rich fractions were proportionally higher in VM plants, leading to a decrease in cell viability and cell membrane damages. It is concluded that not only the intensity but also the nature of physiological responses in Miscanthus x giganteus may drastically differ depending on the pollution level

Vasopressor use after noncardiac surgery: an international observational study

Background: Hypotension after major noncardiac surgery is associated with increased morbidity, mortality, and costs, and is often treated with postoperative vasopressor infusions. The frequency of administration in the postoperative period is unknown. Methods: This international prospective cohort study was conducted between October 2020 and October 2023. At each hospital, adults undergoing noncardiac surgery were enrolled into two cohorts: all consecutive patients for 1 week (Cohort A) and an additional sample of up to 30 consecutive patients administered postoperative vasopressor infusions within 1 yr (Cohort B). The primary outcome (Cohort A) was the incidence of postoperative vasopressor infusions, defined as any continuous infusion of vasopressors. Secondary outcomes included in-hospital mortality, organ dysfunction, length of hospital stay, and complications associated with postoperative vasopressor infusions (both cohorts). Results: In total, 25 675 participants were enrolled from 228 hospitals across 42 countries. In Cohort A, 770/19 768 (3.9%) participants received postoperative vasopressor infusions, with vasopressor use ranging between 0% and 18% across hospitals (median odds ratio: 2.30 [credible interval 1.96–2.73]). This variability did not alter after adjustment for case-mix and procedural characteristics. For both cohorts, postoperative vasopressor infusions were associated with higher (15.5%) in-hospital mortality, higher rates of organ failure, and longer hospital stay. Conclusions: Administration of postoperative vasopressors after noncardiac surgery varied across hospitals and was associated with worse outcomes. Variable practice across hospitals could not be explained by differences in case-mix. Clinical trial registration: https://clinicaltrials.gov/study/NCT03805230, ESAIC tracking ID: ESAIC_CTN_SQUEEZE