Selective elimination of bacterial faecal indicators in the <em>Schmutzdecke</em> of slow sand filtration columns.

Slow sand filtration (SSF) is an effective low-tech water treatment method for pathogen and particle removal. Yet despite its application for centuries, it has been uncertain to which extent pathogenic microbes are removed by mechanical filtration or due to ecological interactions such as grazing and competition for nutrients. In this study, we quantified the removal of bacterial faecal indicators, Escherichia coli and Enterococcus faecalis, from secondary effluent of a wastewater treatment plant and analysed the microbial community composition in compartments of laboratory model SSF columns. The columns were packed with different sand grain sizes and eliminated 1.6-2.3 log units of faecal indicators, which translated into effluents of bathing water quality according to the EU directive (&lt;500 colony forming units of E. coli per 100&nbsp;ml) for columns with small grain size. Most of that removal occurred in the upper filter area, the Schmutzdecke. Within that same zone, total bacterial numbers increased however, thus suggesting a specific elimination of the faecal indicators. The analysis of the microbial communities also revealed that some taxa were removed more from the wastewater than others. These results accentuate the contribution of biological mechanisms to water purification in SSF

Circular polarization immunity of the cyclotron resonance photoconductivity in two-dimensional electron systems

Studying the cyclotron resonance (CR) induced photoconductivity in GaAs and HgTe two-dimensional electron structures under circularly polarized terahertz illumination, we observed an anomalous resonant photoresponse for the CR inactive helicity of almost the same magnitude as for the CR active helicity. This observation conflicts with simultaneous transmission measurements and fundamentally contradicts the conventional theory of CR. We provide a possible route to explain such a basic failure of the conventional description of light-matter interaction and discuss a modified electron dynamics near strong impurities that may provide a local near-field coupling of the two helicity modes. This should result in a CR enhanced absorption for both magnetic field polarities

Resonant Coupling of Ion-Cyclotron Waves to Energetic Helium-Ions

First measurements were performed to test a model prediction which states that the off-axis coupling of ion-cyclotron waves to energetic helium ions can generate either an inward or an outward drift of these particles. Ion-cyclotron waves with a power or up to 1 MW are coupled to energetic particles at the high field side, the low field side, or in the center by varying the toroidal magnetic field. When changing the heating power or the resonance location, the variation of the concentration of the energetic helium in the plasma agrees qualitatively with the model predictions

Low-dose vs high-dose paclitaxel-coated balloons for femoropopliteal lesions: 2-Year results from the COMPARE Trial.

Background: So far only 1-year data have been reported for direct comparisons of paclitaxel-coated balloons (PCBs) using different coating technologies. Objectives: The aim of this study was to report the 24-month results on the efficacy and safety of low-dose vs high-dose PCBs with nominal paclitaxel densities of 2.0 and 3.5 μg/mm2 and different coating technologies for femoropopliteal interventions from the COMPARE (Compare I Pilot Study for the Treatment of Subjects With Symptomatic Femoropopliteal Artery Disease) trial. Procedural characteristics of clinically driven (CD) target lesion revascularization (TLR) were analyzed. Methods: Within a prospective, multicenter, clinical trial, 414 patients with symptomatic femoropopliteal lesions (Rutherford categories 2-4, maximum lesion length 30 cm) were randomly assigned in a 1:1 ratio to endovascular treatment with either a low-dose (Ranger) or a high-dose (IN.PACT) PCB after stratification for lesion length. Two-year follow-up included assessment of primary patency (defined as absence of CD TLR or binary restenosis with a peak systolic velocity ratio &gt;2.4 by duplex ultrasound), safety, and functional and clinical outcomes. Results: At 2 years, the Kaplan-Meier estimates of primary patency were 70.6% and 71.4% for the low-dose and high-dose PCBs (log-rank P = 0.96), respectively. One major amputation occurred in the high-dose group, and rates of all-cause mortality (3.6% vs 2.2%; P = 0.55) and CD TLR (17.3% vs 13.0%; P = 0.31) were similar between the groups. Among a total of 57 CD TLRs, 44.6% were performed for reocclusion and 28.1% for in-stent restenosis. Functional and clinical benefits over baseline were sustained in both groups. Conclusions: The 2-year results of the COMPARE trial demonstrate a sustained treatment benefit of both low-dose and high-dose PCBs for femoropopliteal interventions including a wide range of lesion lengths. (Compare I Pilot Study for the Treatment of Subjects With Symptomatic Femoropopliteal Artery Disease; NCT02701543

High confinement and high density with stationary plasma energy and strong edge radiation in the TEXTOR-94 tokamak

Stationary high energy confinement is observed on TEXTOR-94 for times limited only by the flux swing of the transformer using strong edge radiation cooling. Necessary tools are the feedback control of the radiated power and of the plasma energy content. At the highest densities obtained (up to 1.2 times the Greenwald limit), energy confinement exceeds the edge-localized-mode-free H-mode scaling ITERH93-P by more than 20%. beta limits of TEXTOR-94 are reached with f(H89)/q(a) approximate to 0.6 No detrimental effect of the seeded impurity is seen. These high confinement discharges meet many conditions necessary for a fusion reactor regime