110 research outputs found

    Genome-scale co-expression network comparison across escherichia coli and salmonella enterica serovar typhimurium reveals significant conservation at the regulon level of local regulators despite their dissimilar lifestyles

    Get PDF
    Availability of genome-wide gene expression datasets provides the opportunity to study gene expression across different organisms under a plethora of experimental conditions. In our previous work, we developed an algorithm called COMODO (COnserved MODules across Organisms) that identifies conserved expression modules between two species. In the present study, we expanded COMODO to detect the co-expression conservation across three organisms by adapting the statistics behind it. We applied COMODO to study expression conservation/divergence between Escherichia coli, Salmonella enterica, and Bacillus subtilis. We observed that some parts of the regulatory interaction networks were conserved between E. coli and S. enterica especially in the regulon of local regulators. However, such conservation was not observed between the regulatory interaction networks of B. subtilis and the two other species. We found co-expression conservation on a number of genes involved in quorum sensing, but almost no conservation for genes involved in pathogenicity across E. coli and S. enterica which could partially explain their different lifestyles. We concluded that despite their different lifestyles, no significant rewiring have occurred at the level of local regulons involved for instance, and notable conservation can be detected in signaling pathways and stress sensing in the phylogenetically close species S. enterica and E. coli. Moreover, conservation of local regulons seems to depend on the evolutionary time of divergence across species disappearing at larger distances as shown by the comparison with B. subtilis. Global regulons follow a different trend and show major rewiring even at the limited evolutionary distance that separates E. coli and S. enterica

    Correlation of bandgap reduction with inversion response in (Si)GeSn/high-k/metal stacks.

    Get PDF
    The bandgap tunability of (Si)GeSn group IV semiconductors opens a new era in Si-technology. Depending on the Si/Sn contents, direct and indirect bandgaps in the range of 0.4 eV to 0.8 eV can be obtained, offering a broad spectrum of both photonic and low power electronic applications. In this work, we systematically studied capacitance-voltage characteristics of high-k/metal gate stacks formed on GeSn and SiGeSn alloys with Sn-contents ranging from 0 to 14 at.% and Si-contents from 0 to 10 at.% particularly focusing on the minority carrier inversion response. A clear correlation between the Sn-induced shrinkage of the bandgap energy and enhanced minority carrier response was confirmed using temperature and frequency dependent capacitance voltage-measurements, in good agreement with k.p theory predictions and photoluminescence measurements of the analyzed epilayers as reported earlier. The enhanced minority generation rate for higher Sn-contents can be firmly linked to the bandgap reduction in the GeSn epilayer without significant influence of substrate/interface effects. It thus offers a unique possibility to analyze intrinsic defects in (Si)GeSn epilayers. The extracted dominant defect level for minority carrier inversion lies approximately 0.4 eV above the valence band edge in the studied Sn-content range (0 to12.5 at.%). This finding is of critical importance since it shows that the presence of Sn by itself does not impair the minority carrier lifetime. Therefore, the continuous improvement of (Si)GeSn material quality should yield longer non-radiative recombination times which are required for the fabrication of efficient light detectors and to obtain room temperature lasing action

    Modulation of Sn concentration in ZnO nanorod array: intensification on the conductivity and humidity sensing properties

    Get PDF
    Tin (Sn)-doped zinc oxide (ZnO) nanorod arrays (TZO) were synthesized onto aluminum-doped ZnO-coated glass substrate via a facile sonicated sol–gel immersion method for humidity sensor applications. These nanorod arrays were grown at different Sn concentrations ranging from 0.6 to 3 at.%. X-ray diffraction patterns showed that the deposited TZO arrays exhibited a wurtzite structure. The stress/strain condition of the ZnO film metamorphosed from tensile strain/compressive stress to compressive strain/tensile stress when the Sn concentrations increased. Results indicated that 1 at.% Sn doping of TZO, which has the lowest tensile stress of 0.14 GPa, generated the highest conductivity of 1.31 S cm− 1. In addition, 1 at.% Sn doping of TZO possessed superior sensitivity to a humidity of 3.36. These results revealed that the optimum performance of a humidity-sensing device can be obtained mainly by controlling the amount of extrinsic element in a ZnO film

    Search for an invisible ZZ^\prime in a final state with two muons and missing energy at Belle II

    Full text link
    The LμLτL_{\mu}-L_{\tau} extension of the standard model predicts the existence of a lepton-flavor-universality-violating ZZ^{\prime} boson that couples only to the heavier lepton families. We search for such a ZZ^\prime through its invisible decay in the process e+eμ+μZe^+ e^- \to \mu^+ \mu^- Z^{\prime}. We use a sample of electron-positron collisions at a center-of-mass energy of 10.58GeV collected by the Belle II experiment in 2019-2020, corresponding to an integrated luminosity of 79.7fb1^{-1}. We find no excess over the expected standard-model background. We set 90%\%-confidence-level upper limits on the cross section for this process as well as on the coupling of the model, which ranges from 3×1033 \times 10^{-3} at low ZZ^{\prime} masses to 1 at ZZ^{\prime} masses of 8GeV/c2GeV/c^{2}

    Tests of light-lepton universality in angular asymmetries of B0DνB^0 \to D^{*-} \ell \nu decays

    Full text link
    We present the first comprehensive tests of light-lepton universality in the angular distributions of semileptonic \Bz-meson decays to charged spin-1 charmed mesons. We measure five angular-asymmetry observables as functions of the decay recoil that are sensitive to lepton-universality-violating contributions. We use events where one neutral \B is fully reconstructed in \PUpsilonFourS{} \to\B\overline{B} decays in data corresponding to \lumion integrated luminosity from electron-positron collisions collected with the \belletwo detector. We find no significant deviation from the standard model expectations

    Measurement of C ⁣PC\!P asymmetries and branching-fraction ratios for B±DK±B^\pm \to DK^\pm and Dπ±D\pi^\pm with DKS0K±πD\to K^0_{\rm S} K^\pm\pi^\mp using Belle and Belle II data

    Full text link
    We measure C ⁣PC\!P asymmetries and branching-fraction ratios for B±DK±B^\pm \to DK^\pm and Dπ±D\pi^\pm decays with DKS0K±πD\to K^0_{\rm S} K^\pm\pi^\mp, where DD is a superposition of D0D^0 and Dˉ0\bar{D}^0. We use the full data set of the Belle experiment, containing 772×106 BBˉ772\times 10^6~B\bar{B} pairs, and data from the Belle~II experiment, containing 387×106 BBˉ387\times 10^6~B\bar{B} pairs, both collected in electron-positron collisions at the Υ(4S)\Upsilon(4S) resonance. Our results provide model-independent information on the unitarity triangle angle ϕ3\phi_3.Comment: 26 pages, 8 figure

    Measurement of the branching fraction and CP\it CP asymmetry of B0π0π0B^{0} \rightarrow \pi^{0} \pi^{0} decays using 198×106198 \times 10^6 BBB\overline{B} pairs in Belle II data

    Full text link
    We report measurements of the branching fraction and CP\it CP asymmetry in B0π0π0B^{0} \to \pi^{0} \pi^{0} decays reconstructed at Belle II in an electron-positron collision sample containing 198×106198 \times 10^{6} BBB\overline{B} pairs. We measure a branching fraction \mathcal{B}(\Bpipi) = (1.38 \pm 0.27 \pm 0.22) \times 10^{-6} and a CP\it CP asymmetry \Acp(\Bpipi) = 0.14 \pm 0.46 \pm 0.07, where the first uncertainty is statistical and the second is systematic

    Precise measurement of the Ds+D^+_s lifetime at Belle II

    Full text link
    We measure the lifetime of the Ds+D_s^+ meson using a data sample of 207 fb1^{-1} collected by the Belle II experiment running at the SuperKEKB asymmetric-energy e+ee^+ e^- collider. The lifetime is determined by fitting the decay-time distribution of a sample of 116×103116\times 10^3 Ds+ϕπ+D_s^+\rightarrow\phi\pi^+ decays. Our result is \tau^{}_{D^+_s} = (498.7\pm 1.7\,^{+1.1}_{-0.8}) fs, where the first uncertainty is statistical and the second is systematic. This result is significantly more precise than previous measurements.Comment: 7 pages, 4 figures, to be submitted to Physical Review Letter

    Search for a τ+τ\tau^+\tau^- resonance in e+eμ+μτ+τe^{+}e^{-}\rightarrow \mu^{+}\mu^{-} \tau^+\tau^- events with the Belle II experiment

    Full text link
    We report the first search for a non-standard-model resonance decaying into τ\tau pairs in e+eμ+μτ+τe^{+}e^{-}\rightarrow \mu^{+}\mu^{-} \tau^+\tau^- events in the 3.6-10 GeV/c2c^{2} mass range. We use a 62.8 fb1^{-1} sample of e+ee^+e^- collisions collected at a center-of-mass energy of 10.58 GeV by the Belle II experiment at the SuperKEKB collider. The analysis probes three different models predicting a spin-1 particle coupling only to the heavier lepton families, a Higgs-like spin-0 particle that couples preferentially to charged leptons (leptophilic scalar), and an axion-like particle, respectively. We observe no evidence for a signal and set exclusion limits at 90% confidence level on the product of cross section and branching fraction into τ\tau pairs, ranging from 0.7 fb to 24 fb, and on the couplings of these processes. We obtain world-leading constraints on the couplings for the leptophilic scalar model for masses above 6.5 GeV/c2c^2 and for the axion-like particle model over the entire mass range
    corecore