Spin Hall Current Driven by Quantum Interferences in Mesoscopic Rashba Rings

We propose an all-electrical nanoscopic structure where {\em pure} spin current is induced in the transverse voltage probes attached to {\em quantum-coherent} one-dimensional ring when conventional unpolarized charge current is injected through its longitudinal leads. Tuning of the Rashba spin-orbit coupling in semiconductor heterostructure hosting the ring generates quasi-periodic oscillations of the predicted spin Hall current due to {\em spin-sensitive quantum-interference effects} caused by the difference in Aharonov-Casher phase acquired by opposite spins states traveling clockwise and counterclockwise. Its amplitude is comparable to the mesoscopic spin Hall current predicted for finite-size two-dimensional electron gases, while it gets reduced in wide two-dimensional or disordered rings.Comment: 5 pages, 4 color figure

3D nanometrology of transparent objects by phase calibration of a basic bright-field microscope for multiple illumination apertures

Optical retrieval of the structure of transparent objects at the nanoscale requires adapted techniques capable of probing their interaction with light. Here, we considered a method based on calibration of the defocusing with partially coherent illumination and explored its phase retrieval capability over a wide range of illumination angles. We imaged: (1) commercial dielectric nanospheres to assess the phase calibration when measured along the optical axis, (2) custom-made nano-steps micropatterned in a glass substrate to assess the phase calibration when measured along the transversal axis, and (3) human cancer cells deposited on a glass substrate to assess the results of the calibration on complex transparent 3-dimensional samples. We first verified the model prediction in the spatial frequency domain and subsequently obtained a consistent and linear phase-calibration for illumination numerical apertures ranging from 0.1 to 0.5. Finally, we studied the dependence of the phase retrieval of a complex nanostructured object on the illumination aperture

Magnetoelectronic Spin Echo

We predict a spin echo in electron transport through layered ferromagnetic-normal-ferromagnetic metal structures: whereas a spin current polarized perpendicular to the magnetization direction decays when traversing a single homogeneous ferromagnet on the scale of the ferromagnetic spin-coherence length, it reappears by adding a second identical but antiparallel ferromagnet. This re-entrant transverse spin current resembles the spin-echo effect in the magnetization of nuclei under pulsed excitations. We propose an experimental setup to measure the magnetoelectronic spin echo.Comment: 4 pages, 2 figure

Health Considerations Regarding Horizontal Transfer of Microbial Transgenes Present in Genetically Modified Crops

The potential effects of horizontal gene transfer on human health are an important item in the safety assessment of genetically modified organisms. Horizontal gene transfer from genetically modified crops to gut microflora most likely occurs with transgenes of microbial origin. The characteristics of microbial transgenes other than antibiotic-resistance genes in market-approved genetically modified crops are reviewed. These characteristics include the microbial source, natural function, function in genetically modified crops, natural prevalence, geographical distribution, similarity to other microbial genes, known horizontal transfer activity, selective conditions and environments for horizontally transferred genes, and potential contribution to pathogenicity and virulence in humans and animals. The assessment of this set of data for each of the microbial genes reviewed does not give rise to health concerns. We recommend including the above-mentioned items into the premarket safety assessment of genetically modified crops carrying transgenes other than those reviewed in the present study

Prospects for detection of detached double white dwarf binaries with Gaia, LSST and LISA

Double white dwarf (DWD) binaries are expected to be very common in the Milky Way, but their intrinsic faintness challenges the detection of these systems. Currently, only a few tens of detached DWDs are know. Such systems offer the best chance of extracting the physical properties that would allow us to address a wealth of outstanding questions ranging from the nature of white dwarfs, over stellar and binary evolution to mapping the Galaxy. In this paper we explore the prospects for detections of ultra-compact (with binary separations of a few solar radii or less) detached DWDs in: 1) optical radiation with Gaia and the LSST and 2) gravitational wave radiation with LISA. We show that Gaia, LSST and LISA have the potential to detect respectively around a few hundreds, a thousand, and 25 thousand DWD systems. Moreover, Gaia and LSST data will extend by respectively a factor of two and seven the guaranteed sample of binaries detected in electromagnetic and gravitational wave radiation, opening the era of multi-messenger astronomy for these sources.Comment: submitted to MNRA

High-quality radio-frequency inductors on silicon using a hybrid ferrite technology

We have realized millimeter-size rf inductors on silicon using a polyimide mold–copper electroplating coil technology. Subsequently, the coils are assembled with magnetic cover plates of commercially available bulk Ni–Zn ferrites of high resistivity. Using the magnetic flux-amplifying ferrite plates, we obtain a 40% enhancement of the inductance and a 25% enhancement of the quality factor (Q510– 20) for frequencies up to 0.2 GHz. Our results indicate the large potential of using bulk ferrites for RF applications in a hybrid inductor assembly process

Cubic millimeter power inductor fabricated in batch-type wafer technology

A hybrid technology for the realization of three-dimensional (3-D) miniaturized power inductors is presented. Our devices consist of planar Cu coils on polyimide substrates, and mm-size ferrite magnetic cores, obtained by three-dimensional micro-patterning of ferrite wafers using powder blasting. The coils are realized using an in-house developed high-resolution polyimide spinning and Cu electroplating process. Winding widths down to 5 um have been obtained and total device volumes are ranging between 1.5 and 10 mm3. Inductive and resistive properties are characterized as a function of frequency; inductance values in the 100 uH range have been obtained

Hybrid flex foil-ferrite technology for miniaturized power and RF applications

A hybrid technology for the realization of threedimensional miniaturized power inductors, transformers and RF inductors is presented. This technology consists of combining planar Cu coils on polyimide substrates with high permeability and high resistivity ferrite cores. For miniaturized power inductors and transformers, high permeability (µr ~2000 Mn-Zn ferrite cores are used. These cores operate up to 10 MHz and are obtained by threedimensional micro-patterning of ferrite wafers using the powder-blasting technique. High resistivity (107 Ohm.cm) Ni-Zn ferrite plates cores are used for the realization of RF inductors. The plates are deposited on top of the coils to enhance the magnetic properties of the inductor at GHz frequencies. The planar Cu coils are realized using an inhouse developed high-resolution polyimide spinning and Cu electroplating process on a flexible support of Kapton. Inductive and resistive properties of the power inductors are characterized as a function of frequency; inductance values in the 1 mH range have been obtained. RF inductors show a 40 % enhancement of the inductance and a 25 % enhancement of the quality factor for frequencies up to 0.2 GHz. Our results indicate the potential of using bulk ferrites in a hybrid assembly process for power and RF applications

Preface to the special issue of Food and Chemical Toxicology on the outcomes of the MARLON project on veterinary epidemiology of potential health impacts of genetically modified feeds in livestock

peer-reviewedPreface to the special issue of Food and Chemical Toxicology on the outcomes of the MARLON project