1,234 research outputs found
Modulation of ecdysal cyst and toxin dynamics of two Alexandrium (Dinophyceae) species under small-scale turbulence
Some dinoflagellate species have shown different physiological responses to certain turbulent conditions. Here we investigate how two levels of turbulent kinetic energy dissipation rates (epsilon = 0.4 and 27 cm(2) s(-3)) affect the PSP toxins and ecdysal cyst dynamics of two bloom forming species, Alexandrium minutum and A. catenella. The most striking responses were observed at the high epsilon generated by an orbital shaker. In the cultures of the two species shaken for more than 4 days, the cellular GTX(1+4) toxin contents were significantly lower than in the still control cultures. In A. minutum this trend was also observed in the C(1+2) toxin content. For the two species, inhibition of ecdysal cyst production occurred during the period of exposure of the cultures to stirring (4 or more days) at any time during their growth curve. Recovery of cyst abundances was always observed when turbulence stopped. When shaking persisted for more than 4 days, the net growth rate significantly decreased in A. minutum (from 0.25 +/- 0.01 day(-1) to 0.19 +/- 0.02 day(-1)) and the final cell numbers were lower (ca. 55.4%) than in the still control cultures. In A. catenella, the net growth rate was not markedly modified by turbulence although under long exposure to shaking, the cultures entered earlier in the stationary phase and the final cell numbers were significantly lower (ca. 23%) than in the control flasks. The described responses were not observed in the experiments performed at the low turbulence intensities with an orbital grid system, where the population development was favoured. In those conditions, cells appeared to escape from the zone of the influence of the grids and concentrated in calmer thin layers either at the top or at the bottom of the containers. This ecophysiological study provides new evidences about the sensitivity to high levels of small-scale turbulence by two life cycle related processes, toxin production and encystment, in dinoflagellates. This can contribute to the understanding of the dynamics of those organisms in nature
Toll-like receptor 2 at the crossroad between cancer cells, the immune system, and the microbiota
Toll-like receptor 2 (TLR2) expressed on myeloid cells mediates the recognition of harmful molecules belonging to invading pathogens or host damaged tissues, leading to inflammation. For this ability to activate immune responses, TLR2 has been considered a player in anti-cancer immunity. Therefore, TLR2 agonists have been used as adjuvants for anti-cancer immunotherapies. However, TLR2 is also expressed on neoplastic cells from different malignancies and promotes their proliferation through activation of the myeloid differentiation primary response protein 88 (MyD88)/nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) pathway. Furthermore, its activation on regulatory immune cells may contribute to the generation of an immunosuppressive microenvironment and of the pre-metastatic niche, promoting cancer progression. Thus, TLR2 represents a double-edge sword, whose role in cancer needs to be carefully understood for the setup of effective therapies. In this review, we discuss the divergent effects induced by TLR2 activation in different immune cell populations, cancer cells, and cancer stem cells. Moreover, we analyze the stimuli that lead to its activation in the tumor microenvironment, addressing the role of danger, pathogen, and microbiota-associated molecular patterns and their modulation during cancer treatments. This information will contribute to the scientific debate on the use of TLR2 agonists or antagonists in cancer treatment and pave the way for new therapeutic avenues
Reflective Toraldo pupil for high-resolution millimeter-wave astronomy
A novel, to the best of our knowledge, beam-shaping reflective surface for high-resolution millimeter/ submillimeter-wave astronomy instruments is presented. The reflector design is based on Toraldo’s superresolution principle and implemented with annulated binary-phase coronae structure inspired by the achromatic magnetic mirror approach. A thin, less than half a free-space wavelength, reflective Toraldo pupil device operated in the W-band has been fabricated using mesh-filter technology developed at Cardiff University. The device has been characterized on a quasi-optical test bench and demonstrated expected reduction of the beam width upon reflection at oblique incidence, while featuring a sidelobe level lower than −10 dB. The proposed reflective Toraldo pupil structure can be easily scaled for upper millimeter and infrared frequency bands as well as designed to transform a Gaussian beam into a flat-top beam with extremely low sidelobe level
Two different acid oxidation syntheses to open C60 fullerene for heavy metal detection
Graphene oxide quantum dots (GOQDs) can be synthesized through a large variety of synthesis methods starting from different carbon allotropes such as nanotubes, graphite, C60 and exploiting various synthesis and reactions. These different approaches have great influence on the properties of the obtained materials, and, consequently, on the potential applications. In this work, Buckminster C60 fullerene has been used to prepare unfolded fullerene nanoparticles (UFNPs) via two distinct synthesis methods namely: Hummer and H2 SO4 + HNO3 solution. The different characteristics of the final materials and the different response in the presence of heavy metal ions have been investigated in view of sensing applications of water contamination
A high temperature superconductor microwave filter working in C-band for the Sardinia Radio Telescope
The interference generated by radio signals of human origin negatively affects the quality of astronomical data and hence the performance of the radio antennae. In this contribution we describe a microwave band-pass filter, created using microstrip planar technology on high temperature superconductor material, for one of the radio astronomical receivers of the Sardinia Radio Telescope. The experimental results obtained at cryogenic temperatures display very low ohmic losses, excellent consistency with the simulations and good repeatability among the various prototypes.Le interferenze generate dai segnali radio antropici limitano la qualità delle osservazioni astronomiche e quindi le prestazioni delle antenne radio. In questo contributo si descrive un filtro passa-banda a microonde realizzato su tecnologia planare in microstriscia su materiale superconduttore ad alta temperatura per uno dei ricevitori radio astronomici del Sardinia Radio Telescope. I risultati sperimentali ottenuti a temperature criogeniche mostrano bassissime perdite ohmiche, un ottimo accordo con le simulazioni ed una buona ripetibilità tra i vari prototipi
Platelet-mediated thrombosis in stenosed canine coronary arteries: Inhibition by nicergoline, a platelet-active alpha-adrenergic antagonist
The effects of nicergoline, a new agent that blocks alpha-adrenergic receptors and inhibits platelet phospholipase, were evaluated in a canine model of platelet-mediated coronary thrombosis. In 48 open chest dogs, the circumflex coronary artery was stenosed by plicating the artery wall with a suture. Thirty-four of the 48 dogs exhibited cyclic reductions in flow in the stenotic vessel, followed by a sudden return to control levels. The reductions in flow were unabated in all but two dogs after heparin administration (1,000 U/kg per h), unaffected by large doses of nitroglycerin and nifedipine and associated with platelet aggregates in the stenotic segment (demonstrated by histologic and electron microscopic examination). These observations support the conclusion that the flow reductions were caused by platelet aggregation rather than by fibrin deposition or vasospasm.Twenty dogs were monitored for 1 hour after heparin administration and then assigned to a control (n = 7) or nicergoline-treated (n = 13; 1 mg/kg intravenously) group. In control dogs, cyclic reductions in flow continued unchanged for another hour, whereas in the treated group they were markedly decreased in 1 dog and completely abolished in the other 12 dogs. Aspirin (30 mg/ kg intravenously) suppressed flow reductions in all control dogs, confirming the primary role of platelet aggregation in the phenomenon.This study provides a modified model of platelet-mediated thrombosis in stenosed coronary arteries. Furthermore, the results indicate that nicergoline can effectively interfere with platelet function in vivo. The potent antithrombotic activity exhibited by nicergoline might enhance the therapeutic usefulness of this vasodilator
Antenna beam characterisation for the global 21cm experiment LEDA and its impact on signal model parameter reconstruction
Cosmic Dawn, the onset of star formation in the early universe, can in
principle be studied via the 21cm transition of neutral hydrogen, for which a
sky-averaged absorption signal, redshifted to MHz frequencies, is predicted to
be {\it O}(10-100)\,mK. Detection requires separation of the 21cm signal from
bright chromatic foreground emission due to Galactic structure, and the
characterisation of how it couples to instrumental response. In this work, we
present characterisation of antenna gain patterns for the Large-aperture
Experiment to detect the Dark Ages (LEDA) via simulations, assessing the
effects of the antenna ground-plane geometries used, and measured soil
properties. We then investigate the impact of beam pattern uncertainties on the
reconstruction of a Gaussian absorption feature. Assuming the pattern is known
and correcting for the chromaticity of the instrument, the foregrounds can be
modelled with a log-polynomial, and the 21cm signal identified with high
accuracy. However, uncertainties on the soil properties lead to
\textperthousand\ changes in the chromaticity that can bias the signal
recovery. The bias can be up to a factor of two in amplitude and up to few \%
in the frequency location. These effects do not appear to be mitigated by
larger ground planes, conversely gain patterns with larger ground planes
exhibit more complex frequency structure, significantly compromising the
parameter reconstruction. Our results, consistent with findings from other
antenna design studies, emphasise the importance of chromatic response and
suggest caution in assuming log-polynomial foreground models in global signal
experiments.Comment: Accepted for publication in MNRA
Patient-level meta-analysis of the EDITION 1, 2 and 3 studies : glycaemic control and hypoglycaemia with new insulin glargine 300 U/ml versus glargine 100 U/ml in people with type 2 diabetes
AimsTo conduct a patient-level meta-analysis of the EDITION 1, 2 and 3 studies, which compared the efficacy and safety of new insulin glargine 300 U/ml (Gla-300) with insulin glargine 100 U/ml (Gla-100) in people with type 2 diabetes (T2DM) on basal and mealtime insulin, basal insulin and oral antihyperglycaemic drugs, or no prior insulin, respectively. MethodsThe EDITION studies were multicentre, randomized, open-label, parallel-group, phase IIIa studies, with similar designs and endpoints. A patient-level meta-analysis of the studies enabled these endpoints to be examined over 6 months in a large population with T2DM (Gla-300, n = 1247; Gla-100, n = 1249). ResultsNo significant study-by-treatment interactions across studies were found, enabling them to be pooled. The mean change in glycated haemoglobin was comparable for Gla-300 and Gla-100 [each -1.02 (standard error 0.03)%; least squares (LS) mean difference 0.00 (95% confidence interval (CI) -0.08 to 0.07)%]. Annualized rates of confirmed (3.9 mmol/l) or severe hypoglycaemia were lower with Gla-300 than with Gla-100 during the night (31% difference in rate ratio over 6 months) and at any time (24 h, 14% difference). Consistent reductions were observed in percentage of participants with 1 hypoglycaemic event. Severe hypoglycaemia at any time (24 h) was rare (Gla-300: 2.3%; Gla-100: 2.6%). Weight gain was low ( ConclusionGla-300 provides comparable glycaemic control to Gla-100 in a large population with a broad clinical spectrum of T2DM, with consistently less hypoglycaemia at any time of day and less nocturnal hypoglycaemia.Peer reviewe
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