92 research outputs found

    Analysis of Plane Waves Spectra in a Weakly-Disturbed Flat Reverberation Chamber by Information Theory Criteria

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    This work aims to present the impact of disturbing the stationary modes in a rectangular-shaped reverberation chamber by small-dimensioned stirrers. The study focuses on plane wave’s modeling of the electric field inside a flat cavity using information theory criteria. The emphasis is on anisotropy of the number of plane-waves distribution in the cavity and a strong increase near stirrers. The distributions of the plane wave spectra are studied for a set of reverberation chamber configurations at frequencies close to and far superior to the lowest usable frequency

    Biological properties of carotenoids extracted from Halobacterium halobium isolated from a Tunisian solar saltern

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    Background: Bioactive molecules have received increasing attention due to their nutraceutical attributes and anticancer, antioxidant, antiproliferative and apoptosis-inducing properties. This study aimed to investigate the biological properties of carotenoids extracted from Archaea. Methods: Halophilic Archaea strains were isolated from the brine of a local crystallizer pond (TS7) of a solar saltern at Sfax, Tunisia. The most carotenoid-producing strain (M8) was investigated on heptoma cell line (HepG2), and its viability was assessed by the MTT-test. The cells were incubated with different sub-lethal extract rates, with carotenoid concentrations ranging from 0.2 to 1.5 μM. Antioxidant activity was evaluated through exposing the cells to sub-lethal extract concentrations for 24 hours and then to oxidative stress induced by 60 μM arachidonic acid and 50 μM H2O2. Results: Compared to non-treated cells, bacterial carotenoid extracts inhibited HepG2 cell viability (50%). A time and dose effect was observed, with cell viability undergoing a significant (P < 0.05) decrease with extract concentration. After exposure to oxidative stress, control cells underwent a significant (P < 0.05) decrease in viability as compared to the non-treated cells. Conclusions: The bacterial extracts under investigation were noted to exhibit the strongest free radical scavenging activity with high carotenoid concentrations. The carotenoid extract also showed significant antiproliferative activity against HepG2 human cancer cell lines

    Radio Frequency Identification Sensing Chipless Tag for Permittivity Monitoring of Specific Sizes Materials

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    In this paper, a novel Radio Frequency Identification chipless tag for permittivity sensing characterized by a reduced size, an original shape and a low manufacturing cost is presented. The tag consists of a linear shape taken with multiple linear slots etched on the metal patch, ensuring a multi-frequency response. It enables the development of a robust tag with 8 bits as data capacity within a reduced surface is of 17.5×23 mm². Hence, using the frequency Domain Approach, the chipless tag is able to obtain more than 64 different binary states, by the utilization of the frequency shifting technique and the bandwidth distribution. Also, the operating frequency band ranges from 3.5 to 6.5 GHz. The new design is simulated, realized and experimentally validated by a bi-static measurement in the anechoic chamber. Then, preliminary tests are used for defining the Radio Frequency sensing chipless tag for permittivity monitoring, and proving its feasibility to control the evolution of a material over time or after use

    The clinical relevance of oliguria in the critically ill patient : Analysis of a large observational database

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    Funding Information: Marc Leone reports receiving consulting fees from Amomed and Aguettant; lecture fees from MSD, Pfizer, Octapharma, 3 M, Aspen, Orion; travel support from LFB; and grant support from PHRC IR and his institution. JLV is the Editor-in-Chief of Critical Care. The other authors declare that they have no relevant financial interests. Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Urine output is widely used as one of the criteria for the diagnosis and staging of acute renal failure, but few studies have specifically assessed the role of oliguria as a marker of acute renal failure or outcomes in general intensive care unit (ICU) patients. Using a large multinational database, we therefore evaluated the occurrence of oliguria (defined as a urine output 16 years) patients in the ICON audit who had a urine output measurement on the day of admission were included. To investigate the association between oliguria and mortality, we used a multilevel analysis. Results: Of the 8292 patients included, 2050 (24.7%) were oliguric during the first 24 h of admission. Patients with oliguria on admission who had at least one additional 24-h urine output recorded during their ICU stay (n = 1349) were divided into three groups: transient - oliguria resolved within 48 h after the admission day (n = 390 [28.9%]), prolonged - oliguria resolved > 48 h after the admission day (n = 141 [10.5%]), and permanent - oliguria persisting for the whole ICU stay or again present at the end of the ICU stay (n = 818 [60.6%]). ICU and hospital mortality rates were higher in patients with oliguria than in those without, except for patients with transient oliguria who had significantly lower mortality rates than non-oliguric patients. In multilevel analysis, the need for RRT was associated with a significantly higher risk of death (OR = 1.51 [95% CI 1.19-1.91], p = 0.001), but the presence of oliguria on admission was not (OR = 1.14 [95% CI 0.97-1.34], p = 0.103). Conclusions: Oliguria is common in ICU patients and may have a relatively benign nature if only transient. The duration of oliguria and need for RRT are associated with worse outcome.publishersversionPeer reviewe

    Biotechnological approaches for plant viruses resistance: from general to the modern RNA silencing pathway

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