796 research outputs found
Autonomous space processor for orbital debris
The development of an Autonomous Space Processor for Orbital Debris (ASPOD) was the goal. The nature of this craft, which will process, in situ, orbital debris using resources available in low Earth orbit (LEO) is explained. The serious problem of orbital debris is briefly described and the nature of the large debris population is outlined. The focus was on the development of a versatile robotic manipulator to augment an existing robotic arm, the incorporation of remote operation of the robotic arms, and the formulation of optimal (time and energy) trajectory planning algorithms for coordinated robotic arms. The mechanical design of the new arm is described in detail. The work envelope is explained showing the flexibility of the new design. Several telemetry communication systems are described which will enable the remote operation of the robotic arms. The trajectory planning algorithms are fully developed for both the time optimal and energy optimal problems. The time optimal problem is solved using phase plane techniques while the energy optimal problem is solved using dynamic programming
Oxide phosphors for light upconversion; Yb3+ and Tm3+ co-doped Y2BaZnO5
Copyright 2011 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Journal of Applied Physics 109, 063104 (2011) and may be found at
Validation of a new 60 MeV proton beam-line for radiation hardness testing
A 60 MeV proton beam-line has been developed in Nice, France, in
collaboration with the Centre National d'Etudes Spatiales (CNES). Experimental
results are presented here to validate the beam-line for radiation hardness
testing.Comment: RADECS conference 202
Outer Membrane Integrity-Dependent Fluorescence of the Japanese Eel UnaG Protein in Live Escherichia coli Cells
Reporter genes are important tools in many biological disciplines. The discovery of novel
reporter genes is relatively rare. However, known reporter genes are constantly applied to novel
applications. This study reports the performance of the bilirubin-dependent fluorescent protein UnaG
from the Japanese eel Anguilla japonicas in live Escherichia coli cells in response to the disruption of
outer membrane (OM) integrity at low bilirubin (BR) concentrations. Using the E. coli wild-type
strain MC4100, its isogenic OM-deficient mutant strain NR698, and different OM-active compounds,
we show that BR uptake and UnaG fluorescence depend on a leaky OM at concentrations of 10 µM
BR and below, while fluorescence is mostly OM integrity-independent at concentrations above 50 µM
BR. We suggest that these properties of the UnaG–BR couple might be applied as a biosensor as an
alternative to the OM integrity assays currently in use
Place du dispositif intra-utérin dans l arsenal contraceptif de la jeune femme nullipare en soins primaires
Les dispositifs intra-utérins sont le premier moyen de contraception réversible dans le monde. En 2004, l HAS statue que "les DIU ne sont pas uniquement destinés aux multipares". Malgré les nouvelles recommandations, en France leur utilisation chez la nullipare reste marginale : environ 1% des femmes nullipares l'utilisent. L objectif de cette étude était de déterminer les freins à la diffusion du dispositif intra-utérin chez la jeune femme nullipare en soins primaires ambulatoires. Une étude qualitative a été menée auprès de médecins généralistes libéraux ou salariés de l Isère, dans leur cabinet d exercice. Les entretiens enregistrés ont été menés par deux enquêtrices. L étude a été conduite en recherche de variation maximale, suivant un guide d entretien et jusqu à saturation des données. Après retranscription exhaustive des entretiens, une analyse thématique a été réalisée par les deux investigatrices respectant ainsi la triangulation des données. Vingt médecins généralistes ont été interviewés entre janvier et avril 2013. Les freins mis en évidence sont de quatre ordres. Tout d abord ceux liés aux professionnels de santé, qu ils soient médecins généralistes ou gynécologues. Deuxièmement, ceux en rapport avec les patientes nullipares, principalement induits par un manque d information. Troisièmement viennent les freins en lien avec la société et enfin ceux dépendant des laboratoires pharmaceutiques. Chez les médecins généralistes, les réticences restent ancrées, en dépit des nombreuses études et recommandations qui en découlent depuis bientôt 10 ans. Par ailleurs, les médecins favorables à cette méthode se heurtent à un problème de compétence pratique.GRENOBLE1-BU Médecine pharm. (385162101) / SudocSudocFranceF
Antimicrobial Activity of Securamines From the Bryozoan Securiflustra securifrons
Natural products and their derivatives have served as powerful therapeutics against pathogenic microorganisms and are the mainstay of our currently available treatment options to combat infections. As part of our ongoing search for antimicrobial natural products from marine organisms, one fraction prepared from the Arctic marine bryozoan Securiflustra securifrons was found to be active against the human pathogenic bacterium Streptococcus agalactiae (gr. B). Chemical investigation of the fraction revealed that it contained several variants of the highly modified secondary metabolites known as securamines. The securamines are alkaloids sharing a common isoprene-histamine-tryptamine backbone. In this study, we describe the antimicrobial activities of securamine C, E, and H – J (4, 5, and 1-3) and the attempt to deconvolute the mode of action of 1
The impact of food additives, artificial sweeteners and domestic hygiene products on the human gut microbiome and its fibre fermentation capacity
Purpose
This study investigated the effect of food additives, artificial sweeteners and domestic hygiene products on the gut microbiome and fibre fermentation capacity.
Methods
Faecal samples from 13 healthy volunteers were fermented in batch cultures with food additives (maltodextrin, carboxymethyl cellulose, polysorbate-80, carrageenan-kappa, cinnamaldehyde, sodium benzoate, sodium sulphite, titanium dioxide), sweeteners (aspartame-based sweetener, sucralose, stevia) and domestic hygiene products (toothpaste and dishwashing detergent). Short-chain fatty acid production was measured with gas chromatography. Microbiome composition was characterised with 16S rRNA sequencing and quantitative polymerase chain reaction (qPCR).
Results
Acetic acid increased in the presence of maltodextrin and the aspartame-based sweetener and decreased with dishwashing detergent or sodium sulphite. Propionic acid increased with maltodextrin, aspartame-based sweetener, sodium sulphite and polysorbate-80 and butyrate decreased dramatically with cinnamaldehyde and dishwashing detergent. Branched-chain fatty acids decreased with maltodextrin, aspartame-based sweetener, cinnamaldehyde, sodium benzoate and dishwashing detergent. Microbiome Shannon α-diversity increased with stevia and decreased with dishwashing detergent and cinnamaldehyde. Sucralose, cinnamaldehyde, titanium dioxide, polysorbate-80 and dishwashing detergent shifted microbiome community structure; the effects were most profound with dishwashing detergent (R2 = 43.9%, p = 0.008) followed by cinnamaldehyde (R2 = 12.8%, p = 0.016). Addition of dishwashing detergent and cinnamaldehyde increased the abundance of operational taxonomic unit (OTUs) belonging to Escherichia/Shigella and Klebsiella and decreased members of Firmicutes, including OTUs of Faecalibacterium and Subdoligranulum. Addition of sucralose and carrageenan-kappa also increased the abundance of Escherichia/Shigella and sucralose, sodium sulphite and polysorbate-80 did likewise to Bilophila. Polysorbate-80 decreased the abundance of OTUs of Faecalibacterium and Subdoligranulum. Similar effects were observed with the concentration of major bacterial groups using qPCR. In addition, maltodextrin, aspartame-based sweetener and sodium benzoate promoted the growth of Bifidobacterium whereas sodium sulphite, carrageenan-kappa, polysorbate-80 and dishwashing detergent had an inhibitory effect.
Conclusions
This study improves understanding of how additives might affect the gut microbiota composition and its fibre metabolic activity with many possible implications for human health
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