Experimental assessment of drag reduction by traveling waves in a turbulent pipe flow

We experimentally assess the capabilities of an active, open-loop technique for drag reduction in turbulent wall flows recently introduced by Quadrio et al. [J. Fluid Mech., v.627, 161, (2009)]. The technique consists in generating streamwise-modulated waves of spanwise velocity at the wall, that travel in the streamwise direction. A proof-of-principle experiment has been devised to measure the reduction of turbulent friction in a pipe flow, in which the wall is subdivided into thin slabs that rotate independently in the azimuthal direction. Different speeds of nearby slabs provide, although in a discrete setting, the desired streamwise variation of transverse velocity. Our experiment confirms the available DNS results, and in particular demonstrates the possibility of achieving large reductions of friction in the turbulent regime. Reductions up to 33% are obtained for slowly forward-traveling waves; backward-traveling waves invariably yield drag reduction, whereas a substantial drop of drag reduction occurs for waves traveling forward with a phase speed comparable to the convection speed of near-wall turbulent structures. A Fourier analysis is employed to show that the first harmonics introduced by the discrete spatial waveform that approximates the sinusoidal wave are responsible for significant effects that are indeed observed in the experimental measurements. Practical issues related to the physical implementation of this control scheme and its energetic efficiency are briefly discussed.Comment: Article accepted by Phys. Fluids. After it is published, it will be found at http://pof.aip.or

An Almost Subharmonic Instability in the Flow Past Rectangular Cylinders

The three-dimensional instability of the flow past a 5 :1 rectangular cylinder is investigated via Floquet analysis and direct numerical simulations. A quasi-subharmonic (QS) unstable mode is detected, marking an important difference with the flow past bodies with lower aspect ratio and/or with smooth leading edge. The QS mode becomes unstable at Reynolds number (based on the cylinder thickness and free-stream velocity) Re approximate to 480; its spanwise wavelength is approximately three times the cylinder thickness. The structural sensitivity locates the wavemaker region over the longitudinal sides of the cylinder, indicating that the instability is triggered by the mutual inviscid interaction of vortices generated by the leading edge shear layer

Cactus pear pruning residue in agriculture: Unveiling soil-specific responses to enhance water retention

This study examines the effects of incorporating powdered cactus pear pruning waste (PCPPW) on the hydraulic properties of benchmark soils, in line with circular economy principles. The cultivation of cactus pear generates substantial amounts of pruning residues, which offer the potential for nutrient recovery and reuse. Our findings reveal that amending soils with this material has a positive impact on water retention, but it requires a substantial volume, exceeding 20%, which may not be practical for open-field applications. However, this presents promise for the horticultural and floricultural sectors. These results challenge previous assumptions about soil density, plant-available water capacity, and swelling potential, contributing to our understanding of agronomic applications. Notably, the enhancement of drainable water capacity is most significant in less clayey soils, while highly clayey soils experience fewer benefits. These results highlight the importance of considering specific soil conditions when implementing circular economy principles, particularly in soil amendment practices

Shortening of generation cycles in inbred lines of maize (Zea mays L.) through embryo rescue technique

Embryo rescue techniques have been used as an approach to raise hybrids from incompatible crosses. Thesetechniques have also proved to be valuable tools for maize improvement, since they allow reducing the durationof the generation cycles for speed breeding. The aim of this study was to identify an efficient embryo rescueprotocol to evaluate the response of maize (Zea mays L.) embryo culture and compare its generation time (seedto seed) with the generation time of plants obtained by mature seed germination. To this purpose, we evaluatedthe germination efficiency, in vitro protocol efficiency, and days to flowering of three advanced maize inbred linesdeveloped at the National Institute of Agricultural Technology of Argentina. A greenhouse traditional strategywas used as control. The embryo rescue technique allowed obtaining nearly four generations per year comparedto the two generations obtained in greenhouse. All the plants obtained by the embryo rescue technique weremorphologically normal and fertile. The results confirmed the possibility of using embryo rescue strategies tosignificantly reduce the duration of the generation cycles in maize

Immune thrombotic thrombocytopenic purpura: Personalized therapy using ADAMTS-13 activity and autoantibodies

Recently, treatment of immune-mediated thrombotic thrombocytopenic purpura (ITTP) has changed with the advent of caplacizumab in clinical practice. The International Working Group (IWG) has recently integrated the ADAMTS-13 activity/autoantibody monitoring in consensus outcome definitions. We report three ITTP cases during the coronavirus disease 2019 pandemic, that received a systematic evaluation of ADAMTS-13 activity and autoantibodies. We describe how the introduction of caplacizumab and ADAMTS-13 monitoring could change the management of ITTP patients and discuss whether therapeutic choices should be based on the clinical response alone. ADAMTS-13 activity/antibodies were assessed every 5 days. Responses were evaluated according to updated IWG outcome definitions. These kinetics, rather than clinical remission, guided the therapy, allowing early and safe caplacizumab discontinuation and sensible administration of rituximab. Caplacizumab was cautiously discontinued after achieving ADAMTS-13 complete remission. These cases illustrate that prospective ADAMTS-13 evaluation and use of updated IWG definitions may improve real-life patients’ management in the caplacizumab era

Distribution, abundance and biological features of anglerfish (Lophius piscatorius and Lophius budegassa) (Osteichthyes: Lophiiformes) in the Mediterranean Sea

The distribution and biological features of anglerfish (Lophius piscatorius and L. budegassa) in the Mediterranean Sea were analysed from trawl surveys data (MEDITS project, years 1994-1999). The above-mentioned species were widely distributed in the Mediterranean, but differences in abundance were found according to geographic sectors and depths. Most of the collected specimens belonged to the first length cohorts and length distributions also differed at macroarea levels. Mean sizes at female sexual maturity were estimated at 68.5 cm and 66.2 cm total length, respectively for L. piscatorius and L. budegassaPublicado

Ruxolitinib Adherence in Myelofibrosis and Polycythemia Vera: the “RAMP” Italian multicenter prospective study

Ruxolitinib is beneficial in patients with myelofibrosis (MF) and polycythemia vera (PV). Information on ruxolitinib adherence is scant. The Ruxolitinib Adherence in Myelofibrosis and Polycythemia Vera (RAMP) prospective multicenter study (NCT06078319) included 189 ruxolitinib-treated patients. Patients completed the Adherence to Refills and Medications Scale (ARMS) and Distress Thermometer and Problem List (DTPL) at the earliest convenience, after registration in the study, and at later timepoints. At week-0, low adherence (ARMS > 14) and high distress (DT ≥ 4) were declared by 49.7% and 40.2% of patients, respectively. The main reason for low adherence was difficult ruxolitinib supply (49%), intentional (4.3%) and unintentional (46.7%) non-take. In multivariable regression analysis, low adherence was associated to male sex (p = 0.001), high distress (p < 0.001), and treatment duration ≥ 1 year (p = 0.03). Over time, rates of low adherence and high distress remained stable, but unintentional non-take decreased from 47.9% to 26.0% at week-48. MF patients with stable high adherence/low distress were more likely to obtain/maintain the spleen response at week-24. Low adherence to ruxolitinib represents an unmet clinical need that require a multifaceted approach, based on reason behind it (patients characteristics and treatment duration). Its recognition may help distinguishing patients who are truly refractory and those in need of therapy optimization

Bosentan treatment for Raynauds phenomenon and skin fibrosis in patients with Systemic Sclerosis and pulmonary arterial hypertension: an open-label, observational, retrospective study.

Raynaud's phenomenon (RP) and cutaneous fibrosis are the distinctive manifestations of scleroderma, in which Endothelin-1 plays a fundamental pathogenetic role. Bosentan, an Endothelin-1 receptor antagonist used for the treatment of pulmonary arterial hypertension, retards the beginning of new sclerodermic digital ulcers (DU). This open-label, observational, retrospective study verified the effect of Bosentan on RP and skin fibrosis in sclerodermic outpatients affected by pulmonary arterial hypertension without DU. Fourteen subjects (13 women, 1 man; mean age 60 ± 7.5 years; ten with limited and four with diffuse scleroderma) were observed at baseline (T0) and after four (T1), twelve (T2), twenty-four (T3) and forty-eight (T4) weeks during treatment with Bosentan. They were evaluated for daily quantity and duration of RP attacks and skin thickness (using modified Rodnan total skin score, MRSS). Videocapillaroscopic evaluation was performed at TO and T4. Bosentan decreased significantly the number and duration of RP attacks, beginning at T2 (p<0.05). Videocapillaroscopy showed significant improvement of microcirculatory patterns at T4 (p<0.05). MRSS decreased throughout the study, reaching the statistical significance at T3 and T4 (p<0.01) in the whole cohort. The present data suggest that Bosentan is effective in stabilmng the microcirculation involvement and in improving skin fibrosis irrespective of scleroderma patterns