372 research outputs found

    Prognostic value of bronchoalveolar lavage fluid CD103+CD4+/CD4+ ratio in sarcoidosis

    Get PDF
    The CD103+ integrin is an adhesion molecule found on > 95% of intra-epithelial mucosal lymphocytes, but on <2% of circulating lymphocytes. Several studies have shown that the proportion of CD4+ lymphocytes expressing the CD103+ integrin (CD103+CD4+/CD4+ ratio) in bronchoalveolar lavage fluid (BALF) was low in sarcoidosis compared to other interstitial lung diseases, but we previously demonstrated that the difference was insufficient to allow a confident diagnosis of sarcoidosis without tissue biopsy. Whether BALF CD103+CD4+/CD4+ ratio could have prognostic value in sarcoidosis is unknown. To address this issue, we examined the associations between BALF CD103+CD4+/CD4+ ratio and clinical and imaging characteristics in a retrospective series of 115 patients with sarcoidosis. 63% were men, with a median age of 48 years. 47% had radiographic stage I, 49% had stage II, and 4% had stage III or IV. The median BALF lymphocyte count was 43% and the median CD103+CD4+/CD4+ ratio was 17%. A higher CD103+CD4+/CD4+ ratio was significantly associated with a higher radiographic stage at diagnosis (p=0.017) and last visit (p<0.0001), as well as the presence of fibrosis at imaging at diagnosis (p=0.043) and last visit (p=0.032). Besides an inverse correlation with forced vital capacity at diagnosis (β=-0.16, p=0.031), no consistent association was found between the BALF CD103+CD4+/CD4+ ratio at diagnosis and lung function parameters at diagnosis and last visit. We conclude that BALF CD103+CD4+/CD4+ ratio may have prognostic value in sarcoidosis

    Simon Stevin en het hermetisme: Een cultuurhistorische studie naar zijn methodologie

    Get PDF
    Davids, C.A. [Promotor]Frijhoff, W.Th.M. [Copromotor]Stamhuis, I.H. [Copromotor

    Thermodynamic Model of a Very High Efficiency Power Plant Based on a Biomass Gasifier, SOFCs, and a Gas Turbine

    Full text link
    Thermodynamic calculations with a power plant based on a biomass gasifier, SOFCs and a gas turbine are presented. The SOFC anode off-gas which mainly consists of steam and carbon dioxides used as a gasifying agent leading to an allothermal gasification process for which heat is required. Implementation of heat pipes between the SOFC and the gasifier using two SOFC stacks and intercooling the fuel and the cathode streams in between them has shown to be a solution on one hand to drive the allothermal gasification process and on the other hand to cool down the SOFC. It is seen that this helps to reduce the exergy losses in the system significantly. With such a system, electrical efficiency around 73% is shown as achievable

    Frequency-stabilised laser reference system for water vapour spectroscopy and sensing applications

    Get PDF
    To acheive the requirements of DIAL instrument, a frequency detection unit (FDU) was realised for water vapour spectroscopy. For this we have developed and realised an ECDL, which can be adjusted at 935 nm or at 942 nm, a region also considered as possible for the WALES (water vapour lidar experiment in space) transmitter. The second main subsystem of the FDU, a frequency reference unit (FRU), grants short- and long-term frequency stabilities of the ISL. Offset-locking with frequency differences up to 19 GHz has been experimentally demonstrated with the proposed techniqu

    Ice core measurements of 14CH4 show no evidence of methane release from methane hydrates or old permafrost carbon during a large warming event 11,600 years ago

    Get PDF
    Thawing permafrost and marine methane hydrate destabilization in the Arctic and elsewhere have been proposed as large sources of methane to the atmosphere in the future warming world. To evaluate this hypothesis it is useful to ask whether such methane releases happened during past warming events. The two major abrupt warming events of the last deglaciation, Oldest Dryas - Bølling (OD-B, ≈ 14,500 years ago) and Younger Dryas - Preboreal (YD-PB; ≈11,600 years ago), were associated with large (up to 50%) increases in atmospheric methane (CH4) concentrations. The sources of these large warming-driven CH4 increases remain incompletely understood, with possible contributions from tropical and boreal wetlands, thawing permafrost as well as marine CH4 hydrates. We present new measurements of 14C of paleoatmospheric CH4 over the YD-PB transition from ancient ice outcropping at Taylor Glacier, Antarctica. 14C can unambiguously identify CH4 emissions from "old carbon" sources, such as permafrost and CH4 hydrates. The only prior study of paleoatmospheric 14CH4 (from Greenland ice) suggested that wetlands were the main driver of the YD-PB CH4 increase, but the results were weakened by an unexpected and poorly understood 14CH4 component from in situ cosmogenic production directly in near-surface ice. In this new study, we have been able to accurately characterize and correct for the cosmogenic 14CH4 component. All samples from before, during and after the abrupt warming and associated CH4 increase yielded 14CH4 values that are consistent with 14C of atmospheric CO2 at that time, indicating a purely contemporaneous methane source. These new measurements rule out the possibility of large CH4 releases to the atmosphere from methane hydrates or old permafrost carbon in response to the large and rapid YD-PB warming. To the extent that the characteristics of the YD-PB warming are comparable to those of the current anthropogenic warming, our measurements suggest that large future atmospheric methane increases from old carbon sources in the Arctic are unlikely. Instead, our measurements indicate that global wetlands will likely respond to the warming with increased methane emissions. © European Geosciences UnionYellow Posters session, Y7

    Noise properties of an optical frequency comb from a SESAM-mode-locked 1.5-μm solid-state laser stabilized to the 10−13 level

    Get PDF
    We present a detailed investigation of the noise properties of an optical frequency comb generated from a femtosecond diode-pumped solid-state laser operating in the 1.5-μm spectral region. The stabilization of the passively mode-locked Er:Yb:glass laser oscillator, referred to as ERGO, is achieved using pump power modulation for the control of the carrier envelope offset (CEO) frequency and by adjusting the laser cavity length for the control of the repetition rate. The stability and the noise of the ERGO comb are characterized in free-running and in phase-locked operation by measuring the noise properties of the CEO, of the repetition rate, and of a comb line at 1558nm. The comb line is analyzed from the heterodyne beat signal with a cavity-stabilized ultra-narrow-linewidth laser using a frequency discriminator. Two different schemes to stabilize the comb to a radio-frequency (RF) reference are compared. The comb properties (phase noise, frequency stability) are limited in both cases by the RF oscillator used to stabilize the repetition rate, while the contribution of the CEO is negligible at all Fourier frequencies, as a consequence of the low-noise characteristics of the CEO-beat. Alinewidth of ≈150kHz and a fractional frequency instability of 4.2×10−13 at 1s are obtained for an optical comb line at 1558nm. Improved performance is obtained by stabilizing the comb to an optical reference, which is a cavity-stabilized ultra-narrow linewidth laser at 1558nm. The fractional frequency stability of 8×10−14 at 1s, measured in preliminary experiments, is limited by the reference oscillator used in the frequency compariso

    Acoustic barriers as an acoustic deterrent for native potamodromous migratory fish species

    Get PDF
    This study focused on the use of sound playbacks as acoustic deterrents to direct native potamodromous migratory species away from all kind of traps. The effects of two acoustic treatments, a repeated sine sweep up to 2 kHz (sweep-up stimulus) and an intermittent 140 Hz tone, were tested in three fish species native to Iberia: Salmo trutta, Pseudochondrostoma duriense and Luciobarbus bocagei. In contrast with S. trutta, the endemic cyprinids P. duriense and L. bocagei exhibited a strong repulse reaction to the frequency sweep-up sound. The 140 Hz stimulus did not seem to alter significantly the behaviour of any of the studied species. These results highlight the potential of acoustic stimuli as fish behavioural barriers and their application to in situ conservation measures of native Iberian fish populations, to protect them from hydropower dams. In addition, this study shows that acoustic deterrents can be used selectively on target species.The project nº 13737: Original Solutions - ENI and CITAB-UTAD was funded project: ANI/QREN/FEDER. The Science and Technology Foundation, Portugal funded M.C.P.A. (strategic projects UID/MAR/04292/2013 granted to MARE) and P.J.F. (UID/BIA/00329/2013 granted to cE3c). The scientific plan was achieved under European Investment Funds by FEDER/COMPETE/POCI– Operational Competitiveness and Internationalization Programme, under Project POCI-01-0145-FEDER-006958 and National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UID/AGR/04033. The present study was technically supported by Instituto da Conservação da Natureza e Florestas (ICNF – Delegação Norte), namely the facilities at the fish farm “Estação Aquicola de Castrelos”,info:eu-repo/semantics/publishedVersio
    corecore