A flexible beamline combining XUV attosecond pulses with few-femtosecond UV and near-infrared pulses for time-resolved experiments

We describe a beamline where few-femtosecond ultraviolet (UV) pulses are generated and synchronized to few-cycle near-infrared (NIR) and extreme ultraviolet (XUV) attosecond pulses. The UV light is obtained via third-harmonic generation in argon or neon gas when focusing a phase-stabilized NIR driving field inside a glass cell that was designed to support high pressures for enhanced conversion efficiency. A recirculation system allows reducing the large gas consumption required for the nonlinear process. Isolated attosecond pulses are generated using the polarization gating technique, and the photon spectrometer employed to characterize the XUV radiation consists of a new design based on the combination of a spherical varied-line-space grating and a cylindrical mirror. This design allows for compactness while providing a long entrance arm for integrating different experimental chambers. The entire interferometer is built under vacuum to prevent both absorption of the XUV light and dispersion of the UV pulses, and it is actively stabilized to ensure an attosecond delay stability during experiments. This table-top source has been realized with the aim of investigating UV-induced electron dynamics in neutral states of bio-relevant molecules, but it also offers the possibility to implement a manifold of novel time-resolved experiments based on photo-ionization/excitation of gaseous and liquid targets by ultraviolet radiation. UV pump-XUV probe measurements in ethyl-iodide showcase the capabilities of the attosecond beamline

THz-frequency modulation of the Hubbard <i>U</i> in an organic Mott insulator

We use midinfrared pulses with stable carrier-envelope phase offset to drive molecular vibrations in the charge transfer salt ET-F2TCNQ, a prototypical one-dimensional Mott insulator. We find that the Mott gap, which is probed resonantly with 10 fs laser pulses, oscillates with the pump field. This observation reveals that molecular excitations can coherently perturb the electronic on-site interactions (Hubbard U) by changing the local orbital wave function. The gap oscillates at twice the frequency of the vibrational mode, indicating that the molecular distortions couple quadratically to the local charge density.</p

Surface and bulk contribution to Cu(111) quantum efficiency

The quantum efficiency (QE) of Cu(111) is measured for different impinging light angles with photon energies just above the work function. We observe that the vectorial photoelectric effect, an enhancement of the QE due to illumination with light with an electric vector perpendicular to the sample surface, is stronger in the more surface sensitive regime. This can be explained by a contribution to photoemission due to the variation in the electromagnetic potential at the surface. The contributions of bulk and surface electrons can then be determined

A Case of Spondyloarthritis in Patient Affected by Unicentric Castleman's Disease Effectively Managed with Surgery Resection and Tocilizumab Treatment

A 38-year-old woman was referred to our hospital for rheumatologic manifestations (migrant arthritis and tenosynovitis), without psoriasis or family history of psoriasis, gastroenteric manifestations, or recent genitourinary infections. The instrumental and laboratory tests have suggested a diagnosis of undifferentiated seronegative HLA-B27-positive spondyloarthritis with predominantly peripheral involvement. The symptoms were very severe and resistant to anti-inflammatory drugs and steroids. She had a history of hyaline-vascular unicentric Castleman's disease (HBV, HIV, and HHV-8 negative) treated with surgery resection. After a first pharmacological attempt with sulfasalazine (suspended for urticarial rash), we managed the patient with monotherapy tocilizumab 8 mg/kg, with full response of rheumatologic manifestations. The efficacy of tocilizumab was confirmed even after a follow-up of three years. Our experience seems to describe a new late-onset autoimmune disease (only 21 cases described in literature) potentially related to Castleman's disease. The patient experienced marked improvement from IL-6-based therapy (tocilizumab)

Antiphospholipid antibody: laboratory, pathogenesis and clinical manifestations

Antiphospholipid antibodies (aPL) represent a heterogeneous group of antibodies that recognize various antigenic targets including beta2 glycoprotein I (β2GPI), prothrombin (PT), activated protein C, tissue plasminogen activator, plasmin and annexin A2. The most commonly used tests to detect aPL are: lupus anticoagulant (LAC), a functional coagulation assay, anticardiolipin antibody (aCL) and anti-β2GPI antibody (anti-β2GPI), which are enzyme-linked immunoassay (ELISA). Clinically aPL are associated with thrombosis and/or with pregnancy morbidity. Apparently aPL alone are unable to induce thrombotic manifestations, but they increase the risk of vascular events that can occur in the presence of another thrombophilic condition; on the other hand obstetrical manifestations were shown to be associated not only to thrombosis but mainly to a direct antibody effect on the trophoblast