672 research outputs found

    Repulsion of polarized particles from two-dimensional materials

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    Repulsion of nanoparticles, molecules and atoms from surfaces can have important applications in nanomechanical devices, microfluidics, optical manipulation and atom optics. Here, through the solution of a classical scattering problem, we show that a dipole source can experience a robust and strong repulsive force when its near-field interacts with a two-dimensional material that has a metallic character. As an example, the case of graphene is considered, showing that a broad bandwidth of repulsion can be obtained spanning the frequency range 0<ℏω<(5/3)μc0<\hbar\omega<(5/3)\mu_c, where μc{\mu}_c is the chemical potential of graphene, tuneable electrically or by chemical doping

    High number of circulating CD34+ cells in patients with myelophthisis.

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    Hematopoietic Stem Cells High number of circulating CD34+ cells in patients with myelophthisis Six patients with bone marrow micrometastases from solid cancers presented with increased numbers of circulating CD34+ cells; the CD34+ cell counts were very high in some cases. By contrast, no patient with metastatic cancer without bone marrow involvement showed raised numbers of circulating hemopoietic progenitors. haematologica 2005; 90:976-977 (http:/

    Directional scattering from particles under evanescent wave illumination: the role of reactive power

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    Study of photonic spin-orbital interactions, which involves control of the propagation and spatial distributions of light with the polarization of electromagnetic fields, is not only important at the fundamental level but also has significant implications for functional photonic applications that require active tuning of directional light propagation. Many of the experimental demonstrations have been attributed to the spin-momentum locking characteristic of evanescent waves. In this letter, we show another property of evanescent waves: the polarization dependent direction of the imaginary part of the Poynting vector, i.e. reactive power. Based on this property, we propose a simple and robust way to tune the directional far-field scattering from nanoparticles near a surface under evanescent wave illumination by controlling linear polarization and direction of the incident light

    Measurement of spleen volume by ultrasound scanning in patients with thrombocytosis: a prospective study.

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    Spleen size was assessed in 73 patients with thrombocytosis and in 15 healthy subjects, comparing palpation with ultra-sonography (US) measurement of longitudinal diameter and volume. Intraobserver and interobserver variability for volume on US, checked in 12 patients, was very low. Correlation between spleen volume measured by US and that measured by computed tomography was excellent. Splenomegaly was detected by palpation in 25% of patients, by US assessment of longitudinal diameter in 33%, and by US assessment of volume in 52%. After diagnostic work-up, 54 patients had a diagnosis of essential thrombocythemia (ET), 4 of idiopathic myelofibrosis (IMF), and 15 of secondary thrombocytosis (ST). Spleen volume in patients with ST was in the normal range (138 ± 47 mL) and was significantly lower than that in patients with ET or IMF (370 ± 210 mL; P &lt; .001). Thus, US-measured volume was the most sensitive method for identifying nonpalpable splenomegaly in patients with primary myeloproliferative diseases, and it may help in distinguishing these diseases from reactive disorder

    Use of psychiatric inpatient services by heavy users: Findings from a national survey in Italy

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    Indagine epidemiologica nazionale sull'uso dei SPDC da parte dei pazienti piĂą gravi sul versante dell'uso dei Serviz

    The Show Must Go On: A Snapshot of Italian Academic Working Life during Mandatory Work from Home through the Results of a National Survey

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    During the COVID-19 pandemic, universities worldwide have provided continuity to research and teaching through mandatory work from home. Taking into account the specificities of the Italian academic environment and using the Job Demand-Resource-Recovery model, the present study provides, through an online survey, for the first time a description of the experiences of a large sample of academics (N = 2365) and technical and administrative staff (N = 4086) working in Italian universities. The study analyzes the main differences between genders, roles or work areas, in terms of some job demands, recovery experiences, and outcomes, all important dimensions to achieve goals 3, 4, and 5 of the 2030 Agenda for Sustainable Development. The results support the reflections on gender equality measures in universities and provide a general framework useful for further in-depth analysis and development of measures in order to improve well-being (SDG 3), quality of education (SDG 4), and gender equality (SDG 5)

    Experimental demonstration of linear and spinning Janus dipoles for polarisation and wavelength selective near-field coupling

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    The electromagnetic field scattered by nano-objects contains a broad range of wave vectors and can be efficiently coupled to waveguided modes. The dominant contribution to scattering from subwavelength dielectric and plasmonic nanoparticles is determined by electric and magnetic dipolar responses. Here, we experimentally demonstrate spectral and phase selective excitation of Janus dipoles, sources with electric and magnetic dipoles oscillating out of phase, in order to control near-field interference and directional coupling to waveguides. We show that by controlling the polarisation state of the dipolar excitations and the excitation wavelength to adjust their relative contributions, directionality and coupling strength can be fully tuned. Furthermore, we introduce a novel spinning Janus dipole featuring cylindrical symmetry in the near and far field, which results in either omnidirectional coupling or noncoupling. Controlling the propagation of guided light waves via fast and robust near-field interference between polarisation components of a source is required in many applications in nanophotonics and quantum optics
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