247 research outputs found

    High efficiency, diode pumped 170 W Nd:YAG ceramic slab laser

    Get PDF
    A new thin-slab ceramic Nd:YAG laser is presented based on a novel zig-zag configuration. The slab is shaped in such a way that the beam propagates internally bouncing on the thin lateral faces (Edge zig-zag). Preliminary experiments have demonstrated a power extraction of 170 W (CW) at an optical conversion efficiency of 36%. Measurements have also been performed to assess the propagation properties, at least in the thinner transverse direction, of the beam extracted with a simple stable resonator. This laser format appears as a good competitor of the more traditional face-pumped or edge-pumped zig-zag slab laser schemes

    Moderate and severe plaque psoriasis: cost-of-illness study in Italy

    Get PDF
    Psoriasis is a chronic inflammatory, immune-mediated skin disorder that affects 1.5–1.8 million people in Italy. The most common form of the disease is chronic plaque psoriasis, affecting about 90% of psoriasis patients, with about 20%–30% of them suffering from a moderate or severe condition. Little information is available about the economic impact of psoriasis in European countries. The primary objective of this study was to perform a cost-of-illness analysis of patients with moderate and severe plaque psoriasis in Italy. Therefore, direct, indirect costs, and intangible costs (quality of life – QoL) were assessed. In this national, multicenter, prospective, 3-month cost-of-illness study of moderate and severe plaque psoriasis, direct and indirect costs were assessed from the patient, third-party payer (National Health Service, NHS), and societal perspectives. From November 2003 to October 2004 consecutive patients were enrolled over a 1-year period, in order to minimize seasonal fluctuations in disease severity. 150 patients enrolled in 6 investigational sites in Italy, completed the study, and were eligible to be analyzed according to the study protocol. Intangible costs (QoL) were measured using SF36 and DLQI questionnaires. The mean total cost for psoriasis (average Psoriasis Area Severity Index [PASI] score 21.4), including direct and indirect items, was €8,371.61 per patient per year. The mean cost for patients with moderate disease (PASI ≤ 20) was €5,226.04, while the mean cost for patients with more severe disease (PASI > 20) was €11,434.40 per year. Disease heavily affected QoL measured using SF36, and the impairment was greater in patients affected by a more severe form of disease. Moderate and severe plaque psoriasis is associated with extremely high costs, which are related to disease severity. Data from this study show that the more severe plaque psoriasis, the higher the direct and indirect costs for its management. Direct costs are higher than indirect costs; hospitalization represents the most significant item, accounting for 30% of the total expenses. QoL in moderate and severe plaque psoriasis is low compared with the population at large, confirming the high impact of plaque psoriasis on QoL. The relatively high average annual costs per patient point to the need for a more efficient and long-term control of psoriasis

    Relationship between retinal inner nuclear layer, age, and disease activity in progressive MS

    Get PDF
    Objective: To investigate whether inner nuclear layer (INL) thickness as assessed with optical coherence tomography differs between patients with progressive MS (P-MS) according to age and disease activity. Methods: In this retrospective longitudinal analysis, differences in terms of peripapillary retinal nerve fiber layer (pRNFL), ganglion cell layer + inner plexiform layer (GCIPL), INL and T1/T2 lesion volumes (T1LV/T2LV) were assessed between 84 patients with P-MS and 36 sex- and age-matched healthy controls (HCs) and between patients stratified according to age (cut-off: 51 years) and evidence of clinical/MRI activity in the previous 12 months RESULTS: pRNFL and GCIPL thickness were significantly lower in patients with P-MS than in HCs (p = 0.003 and p < 0.0001, respectively). INL was significantly thicker in patients aged < 51 years compared to the older ones and HCs (38.2 vs 36.5 and 36.7 ÎĽm; p = 0.038 and p = 0.04, respectively) and in those who presented MRI activity (new T2/gadolinium-enhancing lesions) in the previous 12 months compared to the ones who did not and HCs (39.5 vs 36.4 and 36.7 ÎĽm; p = 0.003 and p = 0.008, respectively). Recent MRI activity was significantly predicted by greater INL thickness (Nagelkerke R2 0.36, p = 0.001). Conclusions: INL thickness was higher in younger patients with P-MS with recent MRI activity, a criterion used in previous studies to identify a specific subset of patients with P-MS who best responded to disease-modifying treatment. If this finding is confirmed, we suggest that INL thickness might be a useful tool in stratification of patients with P-MS for current and experimental treatment choice

    3-D numerical simulation of Yb:YAG active slabs with longitudinal doping gradient for thermal load effects assessment.

    Get PDF
    We present a study of Yb:YAG active media slabs, based on a ceramic layered structure with different doping levels. We developed a procedure allowing 3D numerical analysis of the slab optical properties as a consequence of the thermal load induced by the pump process. The simulations are compared with a set of experimental results in order to validate the procedure. These structured ceramics appear promising in appropriate geometrical configurations, and thus are intended to be applied in the construction of High Energy Diode Pumped Solid State Laser (DPSSL) systems working in high repetition-rate pulsed regimes. (C) 2014 Optical Society of Americ

    Quantitative analysis of the thermal distortions in a 100 W CW Nd:YAG ceramic slab laser.

    Get PDF
    Making use of an interferometric diagnostic system, we analyze the thermo-mechanical distortions taking place in the slab shaped ceramic Nd:YAG active medium of a 100 W class laser. These distortions are collected in different pumping regimes, both in static situations and during transient warm-up, and compared to the results of computer simulations. This procedure enables us to determine the relevance of different stress causes and thus to increase the specific power extraction of the active slab module
    • …
    corecore