A new strategy to prevent biofilm and clot formation in medical devices: the use of atmospheric non-thermal plasma assisted deposition of silver-based nanostructured coatings

In industrialized countries, health care associated infections, the fourth leading cause of dis- ease, are a major health issue. At least half of all cases of nosocomial infections are associ- ated with medical devices. Antibacterial coatings arise as an important approach to restrict the nosocomial infection rate without side effects and the development of antibiotic resis- tance. Beside nosocomial infections, clot formation affects cardiovascular medical devices and central venous catheters implants. In order to reduce and prevent such infection, we develop a plasma-assisted process for the deposition of nanostructured functional coatings on flat substrates and mini catheters. Silver nanoparticles (Ag NPs) are synthesized exploit- ing in-flight plasma-droplet reactions and are embedded in an organic coating deposited through hexamethyldisiloxane (HMDSO) plasma assisted polymerization. Coating stability upon liquid immersion and ethylene oxide (EtO) sterilization is assessed through chemical and morphological analysis carried out by means of Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). In the perspective of future clinical appli- cation, an in vitro analysis of anti-biofilm effect has been done. Moreover, we employed a murine model of catheter-associated infection which further highlighted the performance of Ag nanostructured films in counteract biofilm formation. The anti-clot performances coupled by haemo- and cytocompatibility assays have also been performed

Solar-type dynamo behaviour in fully convective stars without a tachocline

In solar-type stars (with radiative cores and convective envelopes), the magnetic field powers star spots, flares and other solar phenomena, as well as chromospheric and coronal emission at ultraviolet to X-ray wavelengths. The dynamo responsible for generating the field depends on the shearing of internal magnetic fields by differential rotation. The shearing has long been thought to take place in a boundary layer known as the tachocline between the radiative core and the convective envelope. Fully convective stars do not have a tachocline and their dynamo mechanism is expected to be very different, although its exact form and physical dependencies are not known. Here we report observations of four fully convective stars whose X-ray emission correlates with their rotation periods in the same way as in Sun-like stars. As the X-ray activity - rotation relationship is a well-established proxy for the behaviour of the magnetic dynamo, these results imply that fully convective stars also operate a solar-type dynamo. The lack of a tachocline in fully convective stars therefore suggests that this is not a critical ingredient in the solar dynamo and supports models in which the dynamo originates throughout the convection zone.Comment: 6 pages, 1 figure. Accepted for publication in Nature (28 July 2016). Author's version, including Method

Auditory processing of sine tones before, during and after ECT in depressed patients by fMRI

Our goal was to assess treatment effects of electroconvulsive therapy (ECT) on acoustic processing in major depression. We hypothesized that (1) depression is related to functional alterations in auditory networks, and that (2) pre-treatment alterations in auditory networks are reversible through treatment with ECT. Acoustic perception of 20 severely depressed and 20 age and gender matched healthy controls was investigated by 3 T functional magnetic resonance imaging employing repeated stimulation by sine tones. Prior to ECT, depressed patients presented a multimodal recruitment of additional brain areas including regions of the secondary visual system (cuneus, lingualis) and the medial frontal cortex. During ECT, signal intensities were reduced compared to pre-ECT values and controls. Activation of several regions increased after ECT. Our data suggest that depression is accompanied by cortical dysfunction including impaired auditory processing of non-speech stimuli. This might be based on overall alterations of brain metabolism indicating functional impairment.Martin Christ, Nikolaus Michael, Hermina Hihn, Anne Schuüttke, Carsten Konrad, Bernhard T. Baune, Andreas Jansen, Bettina Pfleidere