A high quality eumelanin thin film featuring efficient reversibility of the water induced conductivity switch and high biocompatibility was obtained,viaammonia-induced solid state polymerization of a 5,6-dihydroxyindole thin film.

In this work, a microfluidic system to investigate the flow behavior of red blood cells in a microcirculation-mimicking network of PDMS microchannels with thickness comparable to cell size is presented. We provide the first quantitative description of cell velocity and shape as a function of the applied pressure drop in such devices. Based on these results, a novel methodology to measure cell membrane viscoelastic properties in converging/diverging flow is developed, and the results are in good agreement with data from the literature. In particular, in the diverging channel the effect of RBC surface viscosity is dominant with respect to shear elasticity. Possible applications include measurements of cell deformability in pathological samples, where reliable methods are still lacking.

Coplanar microwave resonators made of 330 nm-thick superconducting YBa2Cu3O7 have been\ud realized and characterized in a wide temperature (T, 2–100 K) and magnetic field (B, 0–7 T) range.\ud The quality factor (QL) exceeds 104 below 55K and it slightly decreases for increasing fields,\ud remaining 90% of QLðB ¼ 0Þ for B¼7 T and T¼2K. These features allow the coherent coupling\ud of resonant photons with a spin ensemble at finite temperature and magnetic field. To demonstrate\ud this, collective strong coupling was achieved by using di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium\ud organic radical placed at the magnetic antinode of the fundamental mode: the in-plane magnetic\ud field is used to tune the spin frequency gap splitting across the single-mode cavity resonance\ud at 7.75 GHz, where clear anticrossings are observed with a splitting as large as 82 MHz at\ud T¼2K. The spin-cavity collective coupling rate is shown to scale as the square root of the number\ud of active spins in the ensemble

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The problem of coupling multiple spin ensembles through cavity photons is revisited by using PyBTM organic radicals and a high-Tc superconducting coplanar resonator. An exceptionally strong coupling is obtained and up to three spin ensembles are simultaneously coupled. The ensembles are made physically distinguishable by chemically varying the g factor and by exploiting the inhomogeneities of the applied magnetic field. The coherent mixing of the spin and field modes is demonstrated by the observed multiple anticrossing, along with the simulations performed within the input-output formalism, and quantified by suitable entropic measures.PACS numbers: 33.90.+h, 75.50.Xx, 76.30Rn, 07.57.Pt Controlling light-matter interaction at the quantum level is a central problem in modern physics and technology. The paradigmatic system for such investigation is represented by a two-level emitter coupled to a confined mode of the electromagnetic field [1]. The experimental benchmark of a coherent light-matter interaction is the creation of hybridized modes, which can be observed if the coupling between the field and the emitter is larger than that between these and environment. This strongcoupling regime has been achieved by employing a variety of emitters, ranging from Rydberg atoms to superconducting qubits, all characterized by large electric-dipole transition amplitudes [2]. Spin-photon coupling is much weaker, but can be dramatically enhanced by exploiting cooperative phenomena in N -spin ensembles (SEs) [3,4]. In this way, the strong coupling regime has been demonstrated with different spin systems in high quality factor microwave resonators [5][6][7][8]. Along the same lines, experimental evidence of the coherent coupling between 3D-cavity photons and magnons in ferro-and ferri-magnetic crystals has been provided [9-11].Molecular spin systems display features that are potentially exploitable in quantum-information processing [12], such as a wide tunability of the physical parameters and decoherence times exceeding 10 3 the gating times at liquid nitrogen temperature [13][14][15][16]. Organic radicals provide possibly the simplest spin systems, consisting of single unpaired electrons with isotropic g-factors.In addition, the presence of intermolecular exchange interactions in non-diluted ensembles gives rise to exchange narrowing, which averages out the intermolecular dipolar and hyperfine interactions [17]. SEs of organic radicals can thus combine narrow magnetic transitions and high spin densities. For this reason, they are particularly suitable for reaching the strong coupling regime in a microwave cavity [18][19][20], while their versatility inspires the implementation of quantum gates [21].Here we exploit these features in order to demonstrate the coherent coupling between distinguishable SEs. By using (3,5-dichloro-4-pyridyl)bis(2,4,6-trichlorophenyl)methyl radicals (PyBTM) [22], we first show that the strong-coupling regime is largely achieved in a broad temperature range, with values of the cooperativity reachi...

Data on niobium sputtered films obtained by different techniques are presented and discussed. The residual resistivity is shown to be determined by grain boundary scattering. It is then proven that, also in this case, the residual resistivity behaves as a "universal" parameter determining the detailed superconducting properties of the films. The effect of film nonuniformity in the growth direction is also discussed.

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