Selenium biofortification differentially affects sulfur metabolism and accumulation of phytochemicals in two rocket species (Eruca sativa mill. and diplotaxis tenuifolia) grown in hydroponics

Biofortification can be exploited to enrich plants in selenium (Se), an essential micronutrient for humans. Selenium as selenate was supplied to two rocket species, Eruca sativa Mill. (salad rocket) and Diplotaxis tenuifolia (wild rocket), at 0-40 \u3bcM in hydroponics and its effects on the content and profile of sulphur (S)-compounds and other phytochemicals was evaluated. D. tenuifolia accumulated more total Se and selenocysteine than E. sativa, concentrating up to ~300 mg Se kg 121 dry weight from 10-40 \u3bcM Se. To ensure a safe and adequate Se intake, 30 and 4 g fresh leaf material from E. sativa grown with 5 and 10-20 \u3bcM Se, respectively or 4 g from D. tenuifolia supplied with 5 \u3bcM Se was estimated to be optimal for consumption. Selenium supplementation at or above 10 \u3bcM differentially affected S metabolism in the two species in terms of the transcription of genes involved in S assimilation and S-compound accumulation. Also, amino acid content decreased with Se inE. sativa but increased in D. tenuifolia and the amount of phenolics was more reduced in D. tenuifolia. In conclusion, selenate application in hydroponics allowed Se enrichment of rocket. Furthermore, Se at low concentration (5 \u3bcM) did not significantly affect accumulation of phytochemicals and plant defence S-metabolites

Design and Fabrication of Coplanar YBCO Structures on Lithium Niobate Substrates

YBa2Cu3O7-δ (YBCO) with low RF losses has been successfully deposited onto lithium niobate (LNO) to improve the performance of electrooptic Mach-Zender modulators. Epitaxial, c-axis oriented superconducting YBCO thin films have been grown on X-cut LNO single crystals with a yttria-stabilized zirconia (YSZ) buffer layer by RF magnetron sputtering. This buffer layer is needed to obtain good superconducting properties of the YBCO grown. Numerical tools have been developed to analyze CPW structures based on YBCO/YSZ/LNO trilayers, and they indicate that YSZ thickness has to be kept to the minimum necessary for good YBCO growth. With this restriction, the RF losses of YBCO/YSZ/LNO samples have been measured. The results from these measurements are used to quantify the performance enhancement in a Mach-Zender modulator using YBCO electrodes

Five-year Pan-European, longitudinal surveillance of Clostridium difficile ribotype prevalence and antimicrobial resistance: the extended ClosER study

Clostridium difficile infection (CDI) has been primarily treated with metronidazole or vancomycin. High recurrence rates, the emergence of epidemic PCR ribotypes (RTs) and the introduction of fidaxomicin in Europe in 2011 necessitate surveillance of antimicrobial resistance and CDI epidemiology. The ClosER study monitored antimicrobial susceptibility and geographical distribution of C. difficile RTs pre- and post-fidaxomicin introduction. From 2011 to 2016, 28 European countries submitted isolates or faecal samples for determination of PCR ribotype, toxin status and minimal inhibitory concentrations (MICs) of metronidazole, vancomycin, rifampicin, fidaxomicin, moxifloxacin, clindamycin, imipenem, chloramphenicol and tigecycline. RT diversity scores for each country were calculated and mean MIC results used to generate cumulative resistant scores (CRSs) for each isolate and country. From 40 sites, 3499 isolates were analysed, of which 95% (3338/3499) were toxin positive. The most common of the 264 RTs isolated was RT027 (mean prevalence 11.4%); however, RT prevalence varied greatly between countries and between years. The fidaxomicin geometric mean MIC for years 1–5 was 0.04 mg/L; only one fidaxomicin-resistant isolate (RT344) was submitted (MIC ≥ 4 mg/L). Metronidazole and vancomycin geometric mean MICs were 0.46 mg/L and 0.70 mg/L, respectively. Of prevalent RTs, RT027, RT017 and RT012 demonstrated resistance or reduced susceptibility to multiple antimicrobials. RT diversity was inversely correlated with mean CRS for individual countries (Pearson coefficient r = − 0.57). Overall, C. difficile RT prevalence remained stable in 2011–2016. Fidaxomicin susceptibility, including in RT027, was maintained post-introduction. Reduced ribotype diversity in individual countries was associated with increased antimicrobial resistance

The ac magnetic response of mesoscopic type II superconductors

The response of mesoscopic superconductors to an ac magnetic field is numerically investigated on the basis of the time-dependent Ginzburg-Landau equations (TDGL). We study the dependence with frequency $\omega$ and dc magnetic field $H_{dc}$ of the linear ac susceptibility $\chi(H_{dc}, \omega)$ in square samples with dimensions of the order of the London penetration depth. At $H_{dc}=0$ the behavior of $\chi$ as a function of $\omega$ agrees very well with the two fluid model, and the imaginary part of the ac susceptibility, $\chi"(\omega)$, shows a dissipative a maximum at the frequency $\nu_o=c^2/(4\pi \sigma\lambda^2)$. In the presence of a magnetic field a second dissipation maximum appears at a frequency $\omega_p\ll\nu_0$. The most interesting behavior of mesoscopic superconductors can be observed in the $\chi(H_{dc})$ curves obtained at a fixed frequency. At a fixed number of vortices, $\chi"(H_{dc})$ continuously increases with increasing $H_{dc}$. We observe that the dissipation reaches a maximum for magnetic fields right below the vortex penetration fields. Then, after each vortex penetration event, there is a sudden suppression of the ac losses, showing discontinuities in $\chi"(H_{dc})$ at several values of $H_{dc}$. We show that these discontinuities are typical of the mesoscopic scale and disappear in macroscopic samples, which have a continuos behavior of $\chi(H_{dc})$. We argue that these discontinuities in $\chi(H_{dc})$ are due to the effect of {\it nascent vortices} which cause a large variation of the amplitude of the order parameter near the surface before the entrance of vortices.Comment: 12 pages, 9 figures, RevTex

An environmentally benign antimicrobial nanoparticle based on a silver-infused lignin core

Silver nanoparticles have antibacterial properties, but their use has been a cause for concern because they persist in the environment. Here, we show that lignin nanoparticles infused with silver ions and coated with a cationic polyelectrolyte layer form a biodegradable and green alternative to silver nanoparticles. The polyelectrolyte layer promotes the adhesion of the particles to bacterial cell membranes and, together with silver ions, can kill a broad spectrum of bacteria, including Escherichia coli, Pseudomonas aeruginosa and quaternary-amine-resistant Ralstonia sp. Ion depletion studies have shown that the bioactivity of these nanoparticles is time-limited because of the desorption of silver ions. High-throughput bioactivity screening did not reveal increased toxicity of the particles when compared to an equivalent mass of metallic silver nanoparticles or silver nitrate solution. Our results demonstrate that the application of green chemistry principles may allow the synthesis of nanoparticles with biodegradable cores that have higher antimicrobial activity and smaller environmental impact than metallic silver nanoparticles

On the Filter Narrowing Issues in Elastic Optical Networks

This paper describes the problematic filter narrowing effect in the context of next-generation elastic optical networks. First, three possible scenarios are introduced: the transition from an actual fixed-grid to a flexigrid network, the generic full flexi-grid network, and a proposal for a filterless optical network. Next, we investigate different transmission techniques and evaluate the penalty introduced by the filtering effect when considering Nyquist wavelength division multiplexing, single side-band direct-detection orthogonal frequency division multiplexing, and symbol-rate variable dual polarization quadrature amplitude modulation. Also, different approaches to compensate for the filter narrowing effect are discussed. Results show that the specific needs per each scenario can be fulfilled by the aforementioned technologies and techniques or a combination of them, when balancing performance, network reach, and cost

A Nonsimultaneous, Extended, Altruistic-Donor Chain

We report a chain of 10 kidney transplantations, initiated in July 2007 by a single altruistic donor (i.e., a donor without a designated recipient) and coordinated over a period of 8 months by two large paired-donation registries. These transplantations involved six transplantation centers in five states. In the case of five of the transplantations, the donors and their coregistered recipients underwent surgery simultaneously. In the other five cases, “bridge donors” continued the chain as many as 5 months after the coregistered recipients in their own pairs had received transplants. This report of a chain of paired kidney donations, in which the transplantations were not necessarily performed simultaneously, illustrates the potential of this strategy.Economic

Controlling silver nanoparticle exposure in algal toxicity testing - A matter of timing

The aquatic ecotoxicity testing of nanoparticles is complicated by unstable exposure conditions resulting from various transformation processes of nanoparticles in aqueous suspensions. In this study, we investigated the influence of exposure timing on the algal test response to silver nanoparticles (AgNPs), by reducing the incubation time and by aging the AgNPs in algal medium prior to testing. The freshwater green algae Pseudokirchneriella subcapitata were exposed to AgNO(3), NM-300 K (a representative AgNP) and citrate stabilized AgNPs from two different manufacturers (AgNP1 and AgNP2) in a standard algal growth inhibition test (ISO 8692:2004) for 48 h and a short-term (2 h) (14)C-assimilation test. For AgNO(3), similar responses were obtained in the two tests, whereas freshly prepared suspensions of citrate stabilized AgNPs were less toxic in the 2-h tests compared to the 48-h tests. The 2-h test was found applicable for dissolved silver, but yielded non-monotonous concentration–response relationships and poor reproducibility for freshly prepared AgNP suspensions. However, when aging AgNPs in algal medium 24 h prior to testing, clear concentration–response patterns emerged and reproducibility increased. Prolonged aging to 48 h increased toxicity in the 2-h tests whereas aging beyond 48 h reduced toxicity. Our results demonstrate that the outcome of algal toxicity testing of AgNPs is highly influenced not only by the test duration, but also by the time passed from the moment AgNPs are added to the test medium. This time-dependency should be considered when nanomaterial dispersion protocols for ecotoxicity testing are developed