Broad Feshbach resonance in the 6Li-40K mixture

We study the widths of interspecies Feshbach resonances in a mixture of the fermionic quantum gases 6Li and 40K. We develop a model to calculate the width and position of all available Feshbach resonances for a system. Using the model we select the optimal resonance to study the 6Li/40K mixture. Experimentally, we obtain the asymmetric Fano lineshape of the interspecies elastic cross section by measuring the distillation rate of 6Li atoms from a potassium-rich 6Li/40K mixture as a function of magnetic field. This provides us with the first experimental determination of the width of a resonance in this mixture, Delta B=1.5(5) G. Our results offer good perspectives for the observation of universal crossover physics using this mass-imbalanced fermionic mixture.Comment: 4 pages, 2 figure

Feshbach spectroscopy and scattering properties of ultracold Li+Na mixtures

We have observed 26 interspecies Feshbach resonances at fields up to 2050 G in ultracold $^6$Li+$^{23}$Na mixtures for different spin-state combinations. Applying the asymptotic bound-state model to assign the resonances, we have found that most resonances have d-wave character. This analysis serves as guidance for a coupled-channel calculation, which uses modified interaction potentials to describe the positions of the Feshbach resonances well within the experimental uncertainty and to calculate their widths. The scattering length derived from the improved interaction potentials is experimentally confirmed and deviates from previously reported values in sign and magnitude. We give prospects for $^7$Li+$^{23}$Na and predict broad Feshbach resonances suitable for tuning.Comment: 8 pages, 4 figures, version as published in PR

Targeted Precise Quantification of 12 Human Recombinant Uridine-Diphosphate Glucuronosyl Transferase 1A and 2B Isoforms Using Nano-Ultra-High-Performance Liquid Chromatography/Tandem Mass Spectrometry with Selected Reaction Monitoring

Quantification methods employing stable isotope-labeled peptide standards and liquid chromatography–tandem mass spectrometry are increasingly being used to measure enzyme amounts in biologic samples. Isoform concentrations, combined with catalytic information, can be used in absorption, distribution, metabolism, and excretion studies to improve accuracy of in vitro/in vivo predictions. We quantified isoforms of uridine-diphosphate glucuronosyltransferase (UGT) 1A and 2B in 12 commercially available recombinant UGTs (recUGTs) (n = 49 samples) using nano-ultra-high-performance liquid chromatography–tandem mass spectrometry with selected reaction monitoring). Samples were trypsin-digested and analyzed using our previously published method. Two MRMs were collected per peptide and averaged. Where available, at least two peptides were measured per UGT isoform. The assay could detect UGTs in all recombinant preparations: recUGTs 1A1, 1A3, 1A4, 1A6, 1A7, 1A8, 1A9, 1A10, 2B4, 2B7, 2B15, and 2B17, with limit of detection below 1.0 pmol/mg protein for all isoforms. The assay had excellent linearity in the range observed (2–15.5 pmol/mg, after dilution). Examples of concentrations determined were 1465, 537, 538, 944, 865, 698, 604, 791, 382, 1149, 307, and 740 pmol/mg protein for the respective isoforms. There was a 6.9-fold difference between the maximum and minimum recUGT concentrations. The range of concentrations determined indicates that catalytic rates per mg total protein in vitro will not accurately reflect isoform inherent specific activity for a particular drug candidate. This is the first report of a targeted precise quantification of commercially available recUGTs. The assay has potential for use in comparing UGT amounts with catalytic activity determined using probe substrates, thus allowing representation of catalysis as per pmol of UGT isoform

Tuberculosis research in South Africa over the past 30 years: From bench to bedside

The South African Medical Research Council Centre for Tuberculosis Research has a rich history of high-impact research that has influenced our understating of this hyper-epidemic which is further exacerbated by the emergence and spread of drug-resistant forms of the disease. This review aims to summarise the past 30 years of research conducted in the Centre which has influenced the way that tuberculosis (TB) is diagnosed and treated. The review includes the development of new technologies for rapid screening of people with probable TB and the repurposing of human diagnostics for wildlife conservation

Automatically Designing Robot Controllers and Sensor Morphology with Genetic Programming

International audienceGenetic programming provides an automated design strategy to evolve complex controllers based on evolution in nature. In this contribution we use genetic programming to automatically evolve efficient robot controllers for a corridor following task. Based on tests executed in a simulation environment we show that very robust and efficient controllers can be obtained. Also, we stress that it is important to provide sufficiently diverse fitness cases, offering a sound basis for learning more complex behaviour. The evolved controller is successfully applied to real environments as well. Finally, controller and sensor morphology are co-evolved, clearly resulting in an improved sensor configuration

The host metabolite D-serine contributes to bacterial niche specificity through gene selection

Escherichia coli comprise a diverse array of both commensals and niche-specific pathotypes. The ability to cause disease results from both carriage of specific virulence factors and regulatory control of these via environmental stimuli. Moreover, host metabolites further refine the response of bacteria to their environment and can dramatically affect the outcome of the host–pathogen interaction. Here, we demonstrate that the host metabolite, D-serine, selectively affects gene expression in E. coli O157:H7. Transcriptomic profiling showed exposure to D-serine results in activation of the SOS response and suppresses expression of the Type 3 Secretion System (T3SS) used to attach to host cells. We also show that concurrent carriage of both the D-serine tolerance locus (dsdCXA) and the locus of enterocyte effacement pathogenicity island encoding a T3SS is extremely rare, a genotype that we attribute to an ‘evolutionary incompatibility’ between the two loci. This study demonstrates the importance of co-operation between both core and pathogenic genetic elements in defining niche specificity

Recurrent governance challenges in the implementation and alignment of flood risk management strategies: a review

In Europe increasing flood risks challenge societies to diversify their Flood Risk Management Strategies (FRMSs). Such a diversification implies that actors not only focus on flood defence, but also and simultaneously on flood risk prevention, mitigation, preparation and recovery. There is much literature on the implementation of specific strategies and measures as well as on flood risk governance more generally. What is lacking, though, is a clear overview of the complex set of governance challenges which may result from a diversification and alignment of FRM strategies. This paper aims to address this knowledge gap. It elaborates on potential processes and mechanisms for coordinating the activities and capacities of actors that are involved on different levels and in different sectors of flood risk governance, both concerning the implementation of individual strategies and the coordination of the overall set of strategies. It identifies eight overall coordination mechanisms that have proven to be useful in this respect