646 research outputs found

    Control of near-infrared supercontinuum bandwidth by adjusting pump pulse duration

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    We experimentally and numerically investigated the impact of input pump pulse duration on the near-infrared bandwidth of supercontinuum generation in a photonic crystal fiber. We continuously stretched the temporal duration of the input pump laser (centered at 1030 nm) pulses from 500 fs up to 10 ps, while keeping fixed the pump peak power. We observed that the long-wavelength edge of the supercontinuum spectrum is increased by 200 nm as the pump pulse duration grows from 500 fs to 10 ps. We provide a quantitative fit of the experimental results by means of numerical simulations. Moreover, we have explained the observed spectral broadening enhancement induced by pump pulse energy by developing an approximate yet fully analytical model for soliton energy exchange through a series of collisions in the presence of stimulated Raman scattering

    preliminary study of inkjet printed sensors for monitoring cell cultures

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    Abstract An extremely promising methodology able to obtain feedbacks from cell cultures is represented by the direct integration within culture substrates of specific sensitive elements capable to provide information related to cell adhesion, migration, differentiation and growth. At present, the most common materials used in the implementation of sensors monitoring 2D cell culture are noble metals. However, printed electronics allow instead an innovative approach, from both sensor realization technique and utilization of sensitive materials. This project aims to develop and test 2D ink-jet printed sensors, focusing on biocompatible substrates and conductive inks. Both biocompatibility and printability of two different sensor designs were evaluated, followed by electronic measurements that estimate fibroblast adhesion. Preliminary findings show a good biocompatibility of the Kapton® substrate coupled with PEDOT:PSS ink. This solution allowed us to correlate cell adhesion with an increase of impedance module, in agreement with the optical observation. On-going works rely on the evaluation of different materials used for both substrates and inks, addressing the possibility to monitor cardiomyocyte activity

    Spatiotemporal Characterization of Supercontinuum Extending from the Visible to the Mid-Infrared in Multimode Graded-Index Optical Fiber

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    We experimentally demonstrate that pumping a graded-index multimode fiber with sub-ns pulses from a microchip Nd:YAG laser leads to spectrally flat supercontinuum generation with a uniform bell-shaped spatial beam profile extending from the visible to the mid-infrared at 2500\,nm. We study the development of the supercontinuum along the multimode fiber by the cut-back method, which permits us to analyze the competition between the Kerr-induced geometric parametric instability and stimulated Raman scattering. We also performed a spectrally resolved temporal analysis of the supercontinuum emission.Comment: 5 pages 7 figure

    Spatial beam self-cleaning and supercontinuum generation with Yb-doped multimode graded-index fiber taper based on accelerating self-imaging and dissipative landscape

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    We experimentally demonstrate spatial beam self-cleaning and supercontinuum generation in a tapered Ytterbium-doped multimode optical fiber with parabolic core refractive index profile when 1064 nm pulsed beams propagate from wider (122 µm) into smaller (37 µm) diameter. In the passive mode, increasing the input beam peak power above 20 kW leads to a bell-shaped output beam profile. In the active configuration, gain from the pump laser diode permits to combine beam self-cleaning with supercontinuum generation between 520-2600 nm. By taper cut-back, we observed that the dissipative landscape, i.e., a non-monotonic variation of the average beam power along the MMF, leads to modal transitions of self-cleaned beams along the taper length

    Gas6/TAM system: A key modulator of the interplay between inflammation and fibrosis

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    Fibrosis is the result of an overly abundant deposition of extracellular matrix (ECM) due to the fact of repetitive tissue injuries and/or dysregulation of the repair process. Fibrogenesis is a pathogenetic phenomenon which is involved in different chronic human diseases, accounting for a high burden of morbidity and mortality. Despite being triggered by different causative factors, fibrogenesis follows common pathways, the knowledge of which is, however, still unsatisfactory. This represents a significant limit for the development of effective antifibrotic drugs. In the present paper, we aimed to review the current evidence regarding the potential role played in fibrogenesis by growth arrest-specific 6 (Gas6) and its receptors Tyro3 protein tyrosine kinase (Tyro3), Axl receptor tyrosine kinase (Axl), and Mer tyrosine kinase protooncogene (MerTK) (TAM). Moreover, we aimed to review data about the pathogenetic role of this system in the development of different human diseases characterized by fibrosis. Finally, we aimed to explore the potential implications of these findings in diagnosis and treatment

    Resposta de cultivares de trigo à infestação do pulgão Rhopalosiphum padi.

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    O objetivo deste trabalho foi avaliar a resposta de oito cultivares comerciais de trigo (BRS 194, BRS 208, BRS Camboatá, BRS Guabiju, BRS Guamirim, BRS Louro, BRS Timbaúva e BRS Umbu) à infestação do pulgão Rhopalosiphum padi (Hemiptera: Aphididae). O experimento foi realizado na Embrapa Trigo, em telado, em blocos ao acaso, com oito tratamentos e seis repetições, dispostos em parcelas subdivididas. As parcelas principais receberam os tratamentos com e sem infestação de pulgões, e as subparcelas foram compostas pelas cultivares. A infestação com os pulgões (20 adultos ápteros por planta) foi realizada aos 12 dias após a emergência das plantas, quando se encontravam no início do afilhamento, e foi mantida durante 15 dias. As cultivares avaliadas responderam diferentemente à infestação do pulgão R. padi. A cultivar BRS Timbaúva é a mais resistente, e as cultivares BRS Umbu e BRS Guabiju são as mais suscetíveis ao pulgão, quanto ao crescimento e a capacidade produtiva de plantas

    Clinical significance of fluoroscopic patterns specific for the mitotic spindle in patients with reumatic diseases

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    Objective: we proposed to determine the clinical significance of anti-NuMA and anti-HsEg5 antibodies in a group of patients affected with rheumatic diseases. Materials and methods: indirect immunofluorescence on HEp-2000 cells at serum dilution of 1:40 was used to examin 26 sera which had previously showed a "mitotic spindle" fluoroscopic pattern type during laboratory routine. Results: 21 sera (80,7%) were identified with NuMA and 5 (19,3%) with HsEg5 patterns alone or associated with other ANA patterns. However only patients with isolated positiveness and that is 15 with NuMA and 4 with HsEg5 stainings were included in this study. Of the NuMA positive patients 5 were affected with arthropathies associated to different forms of thyroiditis, 2 with seronegative arthritis, 2 with antiphospholipid syndrome, 1 with systemic lupus erythematosus (SLE), 1 with rheumatoid arthritis, 1 with sicca syndrome, 1 with undifferentiated connective tissue disease, 1 with Mycoplasma pneumaniae infection and 1 with retinal thrombosis. Of the HsEg5 positive patients 3 were affected with SLE and 1 with seronegative arthritis. Conclusions: NuMA does not prevail in any defined rheumatic disease, while HsEg5 staining were more frequent (75%) in patients affected with SLE all of whom showing high antibody titres
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