2,097 research outputs found
Capreomycin is active against non-replicating M. tuberculosis
BACKGROUND: Latent tuberculosis infection (LTBI) is affecting one-third of the world population, and activation of LTBI is a substantial source of new cases of tuberculosis. LTBI is caused by tubercle bacilli in a state of non-replicating persistence (NRP), and the goal of this study was to evaluate the activity in vitro of various antimicrobial agents against non-replicating M. tuberculosis. METHODS: To achieve a state of NRP we placed broth cultures of M. tuberculosis (three strains) in anaerobic conditions, and in this model tested all known anti-TB drugs and some other antimicrobial agents (a total of 32 drugs). The potential effect was evaluated by plating samples from broth cultures for determining the number of viable bacteria (CFU/ml) during a prolonged period of cultivation. Besides drug-free controls we used metronidazole for positive controls, the only drug known so far to be effective against tubercle bacilli in anaerobic setting. RESULTS: On a background of non-replicating conditions in drug-free cultures and clear bactericidal effect of metronidazole none of the antimicrobial agents tested produced effect similar to that of metronidazole except capreomycin, which was as bactericidal at the same level as metronidazole. CONCLUSION: The unique ability of capreomycin to be bactericidal in vitro among the anti-TB drugs against non-replicating tubercle bacilli may justify the search for other drugs among peptide antibiotics with similar activity. This phenomenon requires further studies on the mechanism of action of capreomycin, and evaluation of its activity in appropriate animal models
Nano-scale reservoir computing
This work describes preliminary steps towards nano-scale reservoir computing
using quantum dots. Our research has focused on the development of an
accumulator-based sensing system that reacts to changes in the environment, as
well as the development of a software simulation. The investigated systems
generate nonlinear responses to inputs that make them suitable for a physical
implementation of a neural network. This development will enable
miniaturisation of the neurons to the molecular level, leading to a range of
applications including monitoring of changes in materials or structures. The
system is based around the optical properties of quantum dots. The paper will
report on experimental work on systems using Cadmium Selenide (CdSe) quantum
dots and on the various methods to render the systems sensitive to pH, redox
potential or specific ion concentration. Once the quantum dot-based systems are
rendered sensitive to these triggers they can provide a distributed array that
can monitor and transmit information on changes within the material.Comment: 8 pages, 9 figures, accepted for publication in Nano Communication
Networks, http://www.journals.elsevier.com/nano-communication-networks/. An
earlier version was presented at the 3rd IEEE International Workshop on
Molecular and Nanoscale Communications (IEEE MoNaCom 2013
Homophily-based social group formation in a spin-glass self-assembly framework
Homophily, the tendency of humans to attract each other when sharing similar
features, traits, or opinions has been identified as one of the main driving
forces behind the formation of structured societies. Here we ask to what extent
homophily can explain the formation of social groups, particularly their size
distribution. We propose a spin-glass-inspired framework of self-assembly,
where opinions are represented as multidimensional spins that dynamically
self-assemble into groups; individuals within a group tend to share similar
opinions (intra-group homophily), and opinions between individuals belonging to
different groups tend to be different (inter-group heterophily). We compute the
associated non-trivial phase diagram by solving a self-consistency equation for
'magnetization' (combined average opinion). Below a critical temperature, there
exist two stable phases: one ordered with non-zero magnetization and large
clusters, the other disordered with zero magnetization and no clusters. The
system exhibits a first-order transition to the disordered phase. We
analytically derive the group-size distribution that successfully matches
empirical group-size distributions from online communities.Comment: 6 pages, 5 pages of SI, to appear in Phys. Rev. Let
Cultivation de microalgues avec des effluents gazeux d'une cimenterie afin de réduire les gaz à effet de serre
Process for generation of high-producing CHO cell lines for biomanufacturing of biologics using our CHOrcTA platform
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On the correlation between the oxygen in hydrogen content and the catalytic activity of cathode catalysts in PEM water electrolysis
Altogether five platinum group metal (PGM) and PGM-free cathode catalysts were investigated in full PEM water electrolysis cells regarding their polarisation behaviour and their hydrogen and oxygen recombination properties. It was shown that the recombination activity of permeated oxygen and evolved hydrogen within the cathodic catalyst layer correlates with the activity of the oxygen reduction reaction (ORR) which was determined ex situ with linear sweep voltammetry. We found that the investigated PGM-free cathode catalysts had a low activity for the ORR resulting in higher measurable oxygen in hydrogen volume fractions compared to the PGM catalysts, which are more active for the ORR. Out of the three investigated PGM-free catalysts, only one commercially available material based on a Ti suboxide showed a similar good polarisation behaviour as the state of the art cathode catalyst platinum, while its recombination activity was the lowest of all catalysts. In addition to the recombination of hydrogen and oxygen on the electrocatalysts, we found that the prevalent carbon-based cathodic porous transport layers (PTL) also offer catalytically active recombination sites. In comparison to an inactive PTL, the measurable oxygen flux using carbon-based PTLs was lower and the recombination was enhanced by microporous coatings with high surface areas. © 2021 The Author(s)
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