Self-diffusion in granular gases

The coefficient of self-diffusion for a homogeneously cooling granular gas changes significantly if the impact-velocity dependence of the restitution coefficient $\epsilon$ is taken into account. For the case of a constant $\epsilon$ the particles spread logarithmically slow with time, whereas the velocity dependent coefficient yields a power law time-dependence. The impact of the difference in these time dependences on the properties of a freely cooling granular gas is discussed.Comment: 6 pages, no figure

Roux-en-Y gastric bypass surgery of morbidly obese patients induces swift and persistent changes of the individual gut microbiota

BACKGROUND: Roux-en-Y gastric bypass (RYGB) is an effective means to achieve sustained weight loss for morbidly obese individuals. Besides rapid weight reduction, patients achieve major improvements of insulin sensitivity and glucose homeostasis. Dysbiosis of gut microbiota has been associated with obesity and some of its co-morbidities, like type 2 diabetes, and major changes of gut microbial communities have been hypothesized to mediate part of the beneficial metabolic effects observed after RYGB. Here we describe changes in gut microbial taxonomic composition and functional potential following RYGB. METHODS: We recruited 13 morbidly obese patients who underwent RYGB, carefully phenotyped them, and had their gut microbiomes quantified before (n = 13) and 3 months (n = 12) and 12 months (n = 8) after RYGB. Following shotgun metagenomic sequencing of the fecal microbial DNA purified from stools, we characterized the gut microbial composition at species and gene levels followed by functional annotation. RESULTS: In parallel with the weight loss and metabolic improvements, gut microbial diversity increased within the first 3 months after RYGB and remained high 1 year later. RYGB led to altered relative abundances of 31 species (P < 0.05, q < 0.15) within the first 3 months, including those of Escherichia coli, Klebsiella pneumoniae, Veillonella spp., Streptococcus spp., Alistipes spp., and Akkermansia muciniphila. Sixteen of these species maintained their altered relative abundances during the following 9 months. Interestingly, Faecalibacterium prausnitzii was the only species that decreased in relative abundance. Fifty-three microbial functional modules increased their relative abundance between baseline and 3 months (P < 0.05, q < 0.17). These functional changes included increased potential (i) to assimilate multiple energy sources using transporters and phosphotransferase systems, (ii) to use aerobic respiration, (iii) to shift from protein degradation to putrefaction, and (iv) to use amino acids and fatty acids as energy sources. CONCLUSIONS: Within 3 months after morbidly obese individuals had undergone RYGB, their gut microbiota featured an increased diversity, an altered composition, an increased potential for oxygen tolerance, and an increased potential for microbial utilization of macro- and micro-nutrients. These changes were maintained for the first year post-RYGB. TRIAL REGISTRATION: Current controlled trials (ID NCT00810823, NCT01579981, and NCT01993511). ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13073-016-0312-1) contains supplementary material, which is available to authorized users

10.ペースメーカー移植術の経験(第609回千葉医学会例会・第1外科教室談話会)

Five supporting tables. A table caption of each is given within the file. (XLSX 84 kb

Detection and Characterization of Protein Interactions <i>In Vivo</i> by a Simple Live-Cell Imaging Method

<div><p>Over the last decades there has been an explosion of new methodologies to study protein complexes. However, most of the approaches currently used are based on <i>in vitro</i> assays (e.g. nuclear magnetic resonance, X-ray, electron microscopy, isothermal titration calorimetry etc). The accurate measurement of parameters that define protein complexes in a physiological context has been largely limited due to technical constrains. Here, we present PICT (Protein interactions from Imaging of Complexes after Translocation), a new method that provides a simple fluorescence microscopy readout for the study of protein complexes in living cells. We take advantage of the inducible dimerization of FK506-binding protein (FKBP) and FKBP-rapamycin binding (FRB) domain to translocate protein assemblies to membrane associated anchoring platforms in yeast. In this assay, GFP-tagged prey proteins interacting with the FRB-tagged bait will co-translocate to the FKBP-tagged anchor sites upon addition of rapamycin. The interactions are thus encoded into localization changes and can be detected by fluorescence live-cell imaging under different physiological conditions or upon perturbations. PICT can be automated for high-throughput studies and can be used to quantify dissociation rates of protein complexes <i>in vivo</i>. In this work we have used PICT to analyze protein-protein interactions from three biological pathways in the yeast <i>Saccharomyces cerevisiae</i>: Mitogen-activated protein kinase cascade (Ste5-Ste11-Ste50), exocytosis (exocyst complex) and endocytosis (Ede1-Syp1).</p></div

Analysis of the Ste5-Ste11-Ste50 MAPK cascade subcomplex with PICT.

<p>(A) Schematic representation of the Ste5-Ste11-Ste50 assembly. (B) Recruitment of the Ste5-Ste11-Ste50 complex to Pil1-RFP-FKBP anchoring platforms. Ste11-FRB was used as bait. Bait recruitment upon addition of rapamycin was proved in a strain in which Ste11 was tagged with FRB and GFP (left panel). Co-recruitment of Ste50-GFP prey is shown in the right panel. (D) Matrix with representative cells in the GFP channel for each of the six combinations resulting from all components of the studied complex used as bait (FRB-tagged) and prey (GFP-tagged) in PICT assays. (B) and (C) are color-coded as in Figure 1. “RAP” cells were treated with the vehicle, “+RAP” cells were treated with rapamycin. In (C) “▵, +RAP” denotes that the indicated gene has been deleted and the cells have been treated with rapamycin.</p

PICT-FRAP assay.

<p>(A) PICT-FRAP assay to analyze stable and transient interactions. A schematic representation of PICT-FRAP assay color-coded as in Figure 1. Ste11-FRB and Ede1-FRB were used as bait and Ste50-GFP and Syp1-GFP as prey in the respective experiments. For each assay, a frame from the GFP channel is shown corresponding to an anchoring site before, immediately after photobleaching and at the end of the measurements. (B) PICT-FRAP of the Ste11–Ste50 interaction (left) and the Ede1–Syp1 interaction (right). The curves represent the mean ± SD, Ste11–Ste50 (n = 8) and Ede1–Syp1 (n = 12).</p