Active flow control over a backward-facing step using plasma actuation

© 2016 IAA.Due to the more stringent aviation regulations on fuel consumption and noise reduction, the interest for smaller and mechanically less complex devices for flow separation control has increased. Plasma actuators are currently among the most studied typology of devices for active flow control purposes due to their small size and lightweight. In this study, a single dielectric barrier discharge (SDBD) actuator is used on a backward-facing step to assess its effects on the separated turbulent shear layer and its reattachment location. A range of actuating modulation frequencies, related to the natural frequencies of shear layer instability (flapping) and vortex shedding instability, are examined. The particle image velocimetry technique is used to analyse the flow over the step and the reattachment location. The bulk-flow experiments show negligible effects both on the shear layer and on the reattachment location for every frequency considered, and the actuator is not able to induce a sufficient velocity increase at the step separation point

Is kinesiophobia a predictor of early functional performance after total hip replacement? A prospective prognostic cohort study

Background: Considerable attention has been paid to the role of kinesiophobia with respect to knee prosthesis but it has not yet been studied as a prognostic factor of short-term functional performance following total hip replacement. The main purpose of the present study is to examine the possible predictors of early functional performance of patients undergoing total primary hip arthroplasty, including demographics as age, sex and body mass index, preoperative functional ability, type of anaesthesia, level of haemoglobin, pain and level of kinesiophobia before surgery. Secondly, we want to describe the main characteristics of the population with the highest levels of kinesiophobia. Methods: A prospective, prognostic cohort study was carried out. Patients undergoing primary hip replacement were recruited consecutively. The main outcome is the early functional performance achieved by patients after surgery and measured using the Iowa Level of Assistance (ILOA) scale on the fifth postoperative day. Preoperative kinesiophobia was measured by the Tampa Scale and the preoperative functional ability by the Western Ontario and McMaster Osteoarthritis Index (WOMAC). The multivariate analysis was performed by the General Linear Model. The analysis of the population with high levels of kinesiophobia was conducted by identifying a cut-off of 40 compared to the Tampa Scale. Results: Statistical analysis was performed on 269 patients. The average ILOA score recorded was 19.5 (DS 8.3). The levels of kinesiophobia, showed an average score of 35.1 (7.8) and it was not associated with early functional performance. The independent predictive factors include age, sex and body mass index. Kinesiophobia high levels were recorded in 30% of the population and this population had a higher level of pre-operative WOMAC score. Conclusions: Early functional performance after hip replacement surgery was not correlated with the level of kinesiophobia. Three significant factors that describe a population most at risk of not achieving optimal functional performance are increased age, being female and increase in body mass index. In the preoperative phase, high levels of kinesiophobia were associated with more impaired preoperative functional ability. Trial registration: Current Controlled Trials NCT02786121, May 2016. Retrospectively registered

Addition of high C:N crop residues to a P-limited substrate constrains the benefits of arbuscular mycorrhizal symbiosis for wheat P and N nutrition

Many aspects concerning the role of arbuscular mycorrhizal (AM) fungi in plant nutrient uptake from organic sources remain unclear. Here, we investigated the contribution of AM symbiosis to N and P uptake by durum wheat after the addition of a high C:N biomass to a P-limited soil. Plants were grown in pots in the presence or absence of a multispecies AM inoculum, with (Org) or without (Ctr) the addition of (15)N-labelled organic matter (OM). A further treatment, in which (15)N was applied in mineral form (Ctr+N) in the same amount as that supplied in the Org treatment, was also included. Inoculation with AM had positive effects on plant growth in both control treatments (Ctr and Ctr+N), mainly linked to an increase in plant P uptake. The addition of OM, increasing the P available in the soil for the plants, resulted in a marked decrease in the contribution of AM symbiosis to plant growth and nutrient uptake, although the percentage of mycorrhization was higher in the Org treatment than in the controls. In addition, mycorrhization drastically reduced the recovery of (15)N from the OM added to the soil whereas it slightly increased the N recovery from the mineral fertiliser. This suggests that plants and AM fungi probably exert a differential competition for different sources of N available in the soil. On the whole, our results provide a contribution to a better understanding of the conditions under which AM fungi can play an effective role in mitigating the negative effects of nutritional stresses in plants. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00572-021-01031-8

Nitrogen fertilization and arbuscular mycorrhizal fungi do not mitigate the adverse effects of soil contamination with polypropylene microfibers on maize growth

Soil contamination with microplastics may adversely affect soil properties and functions and consequently crop productivity. In this study, we wanted to verify whether the adverse effects of microplastics in the soil on maize plants (Zea mays L.) are due to a reduction in nitrogen (N) availability and a reduced capacity to establish symbiotic relationships with arbuscular mycorrhizal (AM) fungi. To do this, we performed a pot experiment in which a clayey soil was exposed to two environmentally relevant concentrations of polypropylene (PP; one of the most used plastic materials) microfibers (0.4% and 0.8% w/w) with or without the addition of N fertilizer and with or without inoculation with AM fungi. The experiment began after the soil had been incubated at 23 °C for 5 months. Soil contamination with PP considerably reduced maize root and shoot biomass, leaf area, N uptake, and N content in tissue. The adverse effects increased with the concentration of PP in the soil. Adding N to the soil did not alleviate the detrimental effects of PP on plant growth, which suggests that other factors besides N availability played a major role. Similarly, although the presence of PP did not inhibit root colonization by AM fungi (no differences were observed for this trait between the uncontaminated and PP-contaminated soils), the addition of the fungal inoculum to the soil failed to mitigate the negative impact of PP on maize growth. Quite the opposite: mycorrhization further reduced maize root biomass accumulation. Undoubtedly, much research remains to be done to shed light on the mechanisms involved in determining plant behavior in microplastic-contaminated soils, which are most likely complex. This research is a priority given the magnitude of this contamination and its potential implications for human and environmental health

Addition of high C:N crop residues to a P-limited substrate constrains the benefits of arbuscular mycorrhizal symbiosis for wheat P and N nutrition

Many aspects concerning the role of arbuscular mycorrhizal (AM) fungi in plant nutrient uptake from organic sources remain unclear. Here, we investigated the contribution of AM symbiosis to N and P uptake by durum wheat after the addition of a high C:N biomass to a P-limited soil. Plants were grown in pots in the presence or absence of a multispecies AM inoculum, with (Org) or without (Ctr) the addition of 15N-labelled organic matter (OM). A further treatment, in which 15N was applied in mineral form (Ctr+N) in the same amount as that supplied in the Org treatment, was also included. Inoculation with AM had positive effects on plant growth in both control treatments (Ctr and Ctr+N), mainly linked to an increase in plant P uptake. The addition of OM, increasing the P available in the soil for the plants, resulted in a marked decrease in the contribution of AM symbiosis to plant growth and nutrient uptake, although the percentage of mycorrhization was higher in the Org treatment than in the controls. In addition, mycorrhization drastically reduced the recovery of 15N from the OM added to the soil whereas it slightly increased the N recovery from the mineral fertiliser. This suggests that plants and AM fungi probably exert a differential competition for different sources of N available in the soil. On the whole, our results provide a contribution to a better understanding of the conditions under which AM fungi can play an effective role in mitigating the negative effects of nutritional stresses in plants

Reconstructing Ocean-Plate Stratigraphy (OPS) to Understand Accretionary Style and Mélange Fabric:Insights From the Bangong-Nujiang Suture (Tibet, China)

Ocean-plate stratigraphy (OPS) refers to the lithostratigraphic column atop an ocean plate, which becomes scraped off during subduction and preserved in accretionary complex (AC). Herein, based on structural, stratigraphic, and geochronological studies of ACs from the Bangong-Nujiang suture, we demonstrate that OPS can facilitate interpreting structural and compositional heterogeneities in ACs. Carefully correlated OPSs reveal that, on the overall sediment-rich lower plate, different types of basement topography correspond to the accretion of distinct litho-structural assemblages. In particular, subduction of the major, high-relief Zhonggang seamount eroded the earlier margin and was subsequently accreted as coherent seamount slices. In contrast, subduction of the lower-relief, Gaize seamount halted frontal accretion of trailing sediments, which were dragged downward to the seismogenic depth and underplated as pervasive, shear-related broken formations. Such broken formations may fingerprint past lower-relief-seamount subduction in other fossil ACs

Avelumab as second-line therapy for metastatic, platinum-treated urothelial carcinoma in the phase Ib JAVELIN Solid Tumor study: 2-year updated efficacy and safety analysis

BACKGROUND: Anti-programmed cell death ligand 1 (PD-L1)/programmed cell death 1 antibodies have shown clinical activity in platinum-treated metastatic urothelial carcinoma, resulting in regulatory approval of several agents, including avelumab (anti-PD-L1). We report ≥2-year follow-up data for avelumab treatment and exploratory subgroup analyses in patients with urothelial carcinoma. METHODS: Patients with previously treated advanced/metastatic urothelial carcinoma, pooled from two cohorts of the phase Ib JAVELIN Solid Tumor trial, received avelumab 10 mg/kg every 2 weeks until disease progression, unacceptable toxicity or withdrawal. End points included best overall response and progression-free survival (PFS) per RECIST V.1.1, overall survival (OS) and safety. Post hoc analyses included objective response rates (ORRs) in subgroups defined by established high-risk/poor-prognosis characteristics and association between time to response and outcome. RESULTS: 249 patients received avelumab; efficacy was assessed in 242 postplatinum patients. Median follow-up was 31.9 months (range 24-43), and median treatment duration was 2.8 months (range 0.5-42.8). The confirmed ORR was 16.5% (95% CI 12.1% to 21.8%; complete response in 4.1% and partial response in 12.4%). Median duration of response was 20.5 months (95% CI 9.7 months to not estimable). Median PFS was 1.6 months (95% CI 1.4 to 2.7 months) and the 12-month PFS rate was 16.8% (95% CI 11.9% to 22.4%). Median OS was 7.0 months (95% CI 5.9 to 8.5 months) and the 24-month OS rate was 20.1% (95% CI 15.2% to 25.4%). In post hoc exploratory analyses, avelumab showed antitumor activity in high-risk subgroups, including elderly patients and those with renal insufficiency or upper tract disease; ORRs were numerically lower in patients with liver metastases or low albumin levels. Objective response achieved by 3 months versus later was associated with longer OS (median not reached (95% CI 18.9 months to not estimable) vs 7.1 months (95% CI 5.2 to 9.0 months)). Safety findings were consistent with previously reported 6-month analyses. CONCLUSIONS: After ≥2 years of follow-up, avelumab showed prolonged efficacy and acceptable safety in patients with platinum-treated advanced/metastatic urothelial carcinoma, including high-risk subgroups. Survival appeared longer in patients who responded within 3 months. Long-term safety findings were consistent with earlier reports with avelumab treatment in this patient population

MEE-DBD Plasma Actuator Effect on Aerodynamics of a NACA0015 Aerofoil: Separation and 3D Wake

© 2020, Springer Nature Switzerland AG. Dielectric barrier discharge (DBD) plasma actuators have received considerable attention by many researchers for various flow control applications. Having no moving parts, being light-weight, easily manufacturable, and their ability to respond almost instantly are amongst the advantages which has made them a popular flow control device especially for application on aircraft wings. The new configuration of DBDs which uses multiple encapsulated electrodes (MEE) has been shown to produce a superior and more desirable performance over the standard actuator design. The objective of the current study is to examine the effect of this new actuator configuration on the aerodynamic performance of an aerofoil under leading edge separation and wake interaction conditions. The plasma actuator is placed at the leading edge of a symmetric NACA 0015 aerofoil which corresponds to the location of the leading edge slat. The aerofoil is operated in a chord Reynolds number of 0.2×106. Surface pressure measurements along with the mean velocity profile of the wake using pitot measurements are used to determine the lift and drag coefficients, respectively. Particle image velocimetry (PIV) is also utilised to visualise and quantify the induced flow field. The results show improvement in aerodynamic performances of aerofoil under leading edge separation and also facing the wake region

Durability of advanced nanocomposites based on polyethylene oxide and nanodiamonds

Nanodiamonds nanoparticles (NDs) are amongst the most promising materials for multifunctional nanocomposites for various application