Peptides from the Sea Anemone <i>Metridium senile</i> with Modified Inhibitor Cystine Knot (ICK) Fold Inhibit Nicotinic Acetylcholine Receptors

Nicotinic acetylcholine receptors (nAChRs) play an important role in the functioning of the central and peripheral nervous systems, and other organs of living creatures. There are several subtypes of nAChRs, and almost all of them are considered as pharmacological targets in different pathological states. The crude venom of the sea anemone Metridium senile showed the ability to interact with nAChRs. Four novel peptides (Ms11a-1–Ms11a-4) with nAChR binding activity were isolated. These peptides stabilized by three disulfide bridges have no noticeable homology with any known peptides. Ms11a-1–Ms11a-4 showed different binding activity towards the muscle-type nAChR from the Torpedo californica ray. The study of functional activity and selectivity for the most potent peptide (Ms11a-3) revealed the highest antagonism towards the heterologous rat α9α10 nAChR compared to the muscle and α7 receptors. Structural NMR analysis of two toxins (Ms11a-2 and Ms11a-3) showed that they belong to a new variant of the inhibitor cystine knot (ICK) fold but have a prolonged loop between the fifth and sixth cysteine residues. Peptides Ms11a-1–Ms11a-4 could represent new pharmacological tools since they have structures different from other known nAChRs inhibitors

Stimulated Emission up to 2.75 &micro;m from HgCdTe/CdHgTe QW Structure at Room Temperature

Heterostructures with thin Hg(Cd)Te/CdHgTe quantum wells (QWs) are attractive for the development of mid-infrared interband lasers. Of particular interest are room-temperature operating emitters for the short-wavelength infrared range (SWIR, typically defined as 1.7&ndash;3 &mu;m). In this work, we report on the observation of stimulated emission (SE) in the 2.65&ndash;2.75 &micro;m wavelength range at room temperature in an optically pumped HgCdTe QW laser heterostructure. We study a series of three samples with lengths ranging from 2.5 to 7 mm and discuss the effects related to the non-uniformity of the excitation beam profile. SE threshold intensity and the magnitude of pump-induced carrier heating are found to be effectively dependent on the chip size, which should be accounted for in possible designs of HgCdTe-based optical converters. We also pay attention to the problem of active medium engineering in order to push the SE wavelength towards the 3&ndash;5 &micro;m atmospheric window and to lower the SE threshold

Observation of the suppressed Λb0→DpK- decay with D→K+π- and measurement of its CP asymmetry

International audienceA study of Λb0 baryon decays to the DpK- final state is presented based on a proton-proton collision data sample corresponding to an integrated luminosity of 9  fb-1 collected with the LHCb detector. Two Λb0 decays are considered, Λb0→DpK- with D→K-π+ and D→K+π-, where D represents a superposition of D0 and D¯0 states. The latter process is expected to be suppressed relative to the former, and is observed for the first time. The ratio of branching fractions of the two decays is measured, and the CP asymmetry of the suppressed mode, which is sensitive to the Cabibbo-Kobayashi-Maskawa angle γ, is also reported

Simultaneous determination of CKM angle γ\gamma and charm mixing parameters

A combination of measurements sensitive to the CP violation angle γ of the Cabibbo-Kobayashi-Maskawa unitarity triangle and to the charm mixing parameters that describe oscillations between D$^{0}$ and $\overline{D} ^{0}$ mesons is performed. Results from the charm and beauty sectors, based on data collected with the LHCb detector at CERN’s Large Hadron Collider, are combined for the first time. This method provides an improvement on the precision of the charm mixing parameter y by a factor of two with respect to the current world average. The charm mixing parameters are determined to be $x=\left({0.400}_{-0.053}^{+0.052}\right)\%$ and y = $\left({0.630}_{-0.030}^{+0.033}\right)\%$. The angle γ is found to be γ = $\left({65.4}_{-4.2}^{+3.8}\right){}^{\circ}$ and is the most precise determination from a single experiment.[graphic not available: see fulltext

Simultaneous determination of CKM angle γ\gamma and charm mixing parameters

International audienceA combination of measurements sensitive to the CP violation angle γ of the Cabibbo-Kobayashi-Maskawa unitarity triangle and to the charm mixing parameters that describe oscillations between D$^{0}$ and $\overline{D} ^{0}$ mesons is performed. Results from the charm and beauty sectors, based on data collected with the LHCb detector at CERN’s Large Hadron Collider, are combined for the first time. This method provides an improvement on the precision of the charm mixing parameter y by a factor of two with respect to the current world average. The charm mixing parameters are determined to be $x=\left({0.400}_{-0.053}^{+0.052}\right)\%$ and y = $\left({0.630}_{-0.030}^{+0.033}\right)\%$. The angle γ is found to be γ = $\left({65.4}_{-4.2}^{+3.8}\right){}^{\circ}$ and is the most precise determination from a single experiment.[graphic not available: see fulltext

Angular analysis of the rare decay Bs0 {B}_s^0 → ϕμ+^{+}μ−^{−}

An angular analysis of the rare decay ${B}_s^0$→ ϕμ$^{+}$μ$^{−}$ is presented, using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 8.4 fb$^{−1}$. The observables describing the angular distributions of the decay ${B}_s^0$→ ϕμ$^{+}$μ$^{−}$ are determined in regions of q$^{2}$, the square of the dimuon invariant mass. The results are consistent with Standard Model predictions.[graphic not available: see fulltext

Observation of excited Ωc0\Omega_c^0 baryons in Ωb−→Ξc+K−π−\Omega_b^- \to \Xi_c^+ K^-\pi^-decays

The first observation of the $Ω_b^- → Ξ_c^+ K^- π^-$ decay is reported using p p collision data at center of mass energies of 7, 8, and 13 TeV collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb$^{-1}$. Four excited $Ω_c^0$ baryons are observed in the $Ξ_c^+ K^-$ mass projection of the $Ω_b^-→ Ξ_c^+ K^- π^-$ decays with the significance of each exceeding five standard deviations. They coincide with the states previously observed in prompt pp and $e^+ e^-$ production. Relative production rates, masses, and natural widths of the states are measured, and a test of spin hypotheses is performed. Moreover, the branching ratio of $Ω_b^- → Ξ_c^+ K^- π^-$ is measured relative to the $Ω_b^- → Ω_c^0 π^-$ decay mode and a precise measurement of the $Ω_b^-$ mass of $6044.3±1.2±1.1_{-0.22}^{+0.19}$ MeV is obtained

Observation of a Λb0−Λ‾b0\Lambda_b^0-\overline{\Lambda}_b^0 production asymmetry in proton-proton collisions at s=7 and 8 TeV\sqrt{s} = 7 \textrm{ and } 8\,\textrm{TeV}

International audienceThis article presents differential measurements of the asymmetry between ${\varLambda}_b^0$ and ${\overline{\varLambda}}_b^0$ baryon production rates in proton-proton collisions at centre-of-mass energies of $\sqrt{s}$ = 7 and 8 TeV collected with the LHCb experiment, corresponding to an integrated luminosity of 3 fb$^{−1}$. The ${\varLambda}_b^0$ baryons are reconstructed through the inclusive semileptonic decay ${\varLambda}_b^0$ → ${\varLambda}_c^{+}$μ$^{−} \overline{\nu} _{μ}$X. The production asymmetry is measured both in intervals of rapidity in the range 2.15 < y < 4.10 and transverse momentum in 2 < p$_{T}$< 27 GeV/c. The results are found to be incompatible with symmetric production with a significance of 5.8 standard deviations for both $\sqrt{s}$ = 7 and 8 TeV data, assuming no CP violation in the decay. There is evidence for a trend as a function of rapidity with a significance of 4 standard deviations. Comparisons to predictions from hadronisation models in Pythia and heavy-quark recombination are provided. This result constitutes the first observation of a particle-antiparticle asymmetry in b-hadron production at LHC energies.[graphic not available: see fulltext

Branching Fraction Measurements of the Rare Bs0→ϕμ+μ−B^0_s\rightarrow\phi\mu^+\mu^- and Bs0→f2′(1525)μ+μ−B^0_s\rightarrow f_2^\prime(1525)\mu^+\mu^- Decays

The branching fraction of the rare $B^0_s\rightarrow\phi\mu^+\mu^-$ decay is measured using data collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to integrated luminosities of 1, 2, and 6 fb$^{-1}$, respectively. The branching fraction is reported in intervals of q$^2$, the square of the dimuon invariant mass. In the q$^2$ region between 1.1 and 6.0 GeV$^2$/c$^4$, the measurement is found to lie 3.6 standard deviations below a standard model prediction based on a combination of light cone sum rule and lattice QCD calculations. In addition, the first observation of the rare $B^0_s\rightarrow f_2^\prime(1525)\mu^+\mu^-$ decay is reported with a statistical significance of 9 standard deviations and its branching fraction is determined