Generation of ultrashort (~10ps) spontaneous emission pulses by quantum dots in a switched optical microcavity

We report on the generation of few-ps long spontaneous emission pulses by quantum dots (QDs) in a switched optical microcavity. We use a pulsed optical injection of free charge carriers to induce a large frequency shift of the fundamental mode of a GaAs/AlAs micropillar. We track in real time by time-resolved photoluminescence its fundamental mode during its relaxation, using the emission of the QD ensemble as a broadband internal light source. Sub-ensembles of QDs emitting at a given frequency, interact transiently with the mode and emit an ultrashort spontaneous emission pulse into it. By playing with switching parameters and with the emission frequency of the QDs, selected by spectral filtering, pulse durations ranging from 300 ps down to 6 ps have been obtained. These pulses display a very small coherence length, which opens potential applications in the field of ultrafast imaging. The control of QD-mode coupling on ps-time scales establishes also cavity switching as a key resource for quantum photonics.Comment: 11 pages, 8 figures; includes supplemental materia

Cost-utility analysis of meaning-centered group psychotherapy for cancer survivors

Background: Meaning-centered group psychotherapy for cancer survivors (MCGP-CS) improves meaning, psychological well-being, and mental adjustment to cancer and reduces psychological distress. This randomized controlled trial was conducted to investigate the cost-utility of MCGP-CS compared with supportive group psychotherapy (SGP) and care-as-usual (CAU). Methods: In total, 170 patients were randomized to MCGP-CS, SGP, or CAU. Intervention costs, direct medical and nonmedical costs, productivity losses, and health-related quality of life were measured until 6 months follow-up, using the TIC-P, PRODISQ, data from the hospital information system, and the EQ-5D. The cost-utility was calculated by comparing mean cumulative costs and quality-adjusted life years (QALYs). Results: Mean total costs ranged from €4492 (MCGP-CS) to €5304 (CAU). Mean QALYs ranged.507 (CAU) to.540 (MCGP-CS). MCGP-CS had a probability of 74% to be both less costly and more effective than CAU, and 49% compared with SGP. Sensitivity analyses showed these findings are robust. If society is willing to pay €0 for one gained QALY, MCGP-CS has a 78% probability of being cost-effective compared with CAU. This increases to 85% and 92% at willingness-to-pay thresholds of €10 000 and €30 000, which are commonly accepted thresholds. Conclusions: MCGP-CS is highly likely a cost-effective intervention, meaning that there is a positive balance between the costs and gains of MCGP-CS, in comparison with SGP and CAU

A whisper-game perspective on the family communication of DNA-test results: a retrospective study on the communication process of BRCA1/2-test results between proband and relatives

Objective of this paper is to study how DNA-test result information was communicated and perceived within families. A retrospective descriptive study in 13 probands with a BRCA1/2 unclassified variant, 7 with a pathogenic mutation, 5 with an uninformative result, and in 44, 14, and 12 of their 1st and 2nd degree relatives respectively. We examined differences and correlations between: (a) information actually communicated (b) probands' perception, (c) relatives' perception. The perception consisted of recollections and interpretations of both their own and their relatives' cancer-risks, and heredity-likelihood (i.e. likelihood that cancer is heritable in the family). Differences and low correlations suggested few similarities between the actually communicated information, the probands' and the relatives' perception. More specifically, probands recalled the communicated information differently compared with the actually communicated information (R = .40), and reinterpreted this information differently (R = .30). The relatives' perception was best correlated with the proband's interpretation (R = .08), but this perception differed significantly from their proband's perception. Finally, relatives reinterpreted the information they received from their proband differently (R = .25), and this interpretation was only slightly related with the original message communicated by the genetic-counsellor (R = .15). Unclassified-variants were most frequently misinterpreted by probands and relatives, and had the largest differences between probands' and relatives' perceptions. Like in a children's whisper-game, many errors occur in the transmission of DNA-test result information in families. More attention is required for how probands disseminate information to relatives. Genetic-counsellors may help by supporting the probands in communicating to relatives, e.g. by providing clear summary letters for relatives

Disentangling type 2 diabetes and metformin treatment signatures in the human gut microbiota

In recent years, several associations between common chronic human disorders and altered gut microbiome composition and function have been reported(1,2). In most of these reports, treatment regimens were not controlled for and conclusions could thus be confounded by the effects of various drugs on the microbiota, which may obscure microbial causes, protective factors or diagnostically relevant signals. Our study addresses disease and drug signatures in the human gut microbiome of type 2 diabetes mellitus (T2D). Two previous quantitative gut metagenomics studies of T2D patients that were unstratified for treatment yielded divergent conclusions regarding its associated gut microbial dysbiosis(3,4). Here we show, using 784 available human gut metagenomes, how antidiabetic medication confounds these results, and analyse in detail the effects of the most widely used antidiabetic drug metformin. We provide support for microbial mediation of the therapeutic effects of metformin through short-chain fatty acid production, as well as for potential microbiota-mediated mechanisms behind known intestinal adverse effects in the form of a relative increase in abundance of Escherichia species. Controlling for metformin treatment, we report a unified signature of gut microbiome shifts in T2D with a depletion of butyrate-producing taxa(3,4). These in turn cause functional microbiome shifts, in part alleviated by metformin-induced changes. Overall, the present study emphasizes the need to disentangle gut microbiota signatures of specific human diseases from those of medication

Human intestinal metagenomics:state of the art and future

Over the last few years our understanding of human biology has undergone profound transformation. The key role of the 'world inside us', namely the gut microbiota, once considered a forgotten organ, has been revealed, with strong impact on our health and well-being. The present review highlights the most important recent findings on the role of gut microbiota and its impact on the host and raises crucial questions to be considered in future studies