DichroMatch: a website for similarity searching of circular dichroism spectra

Circular dichroism (CD) spectroscopy is a widely used method for examining the structure, folding and conformational changes of proteins. A new online CD analysis server (DichroMatch) has been developed for identifying proteins with similar spectral characteristics by detecting possible structurally and functionally related proteins and homologues. DichroMatch includes six different methods for determining the spectral nearest neighbours to a query protein spectrum and provides metrics of how similar these spectra are and, if corresponding crystal structures are available for the closest matched proteins, information on their secondary structures and fold classifications. By default, DichroMatch uses all the entries in the Protein Circular Dichroism Data Bank (PCDDB) for its comparison set, providing the broadest range of publicly available protein spectra to match with the unknown protein. Alternatively, users can download or create their own specialized data sets, thereby enabling comparisons between the structures of related proteins such as wild-type versus mutants or homologues or a series of spectra of the same protein under different conditions. The DichroMatch server is freely available at http://dichromatch.cryst.bbk.ac.uk

Factors associated with intracerebral hemorrhage after thrombolytic therapy for ischemic stroke pooled analysis of placebo data from the Stroke-Acute Ischemic NXY Treatment (SAINT) I and SAINT II trials

<p><b>Background and Purpose:</b> A number of factors have been associated with postthrombolysis intracerebral hemorrhage, but these have varied across studies.</p> <p><b>Methods:</b> We examined patients with acute ischemic stroke treated with intravenous tissue plasminogen activator within 3 hours of symptom onset who were enrolled in the placebo arms of 2 trials (Stroke-Acute Ischemic NXY Treatment [SAINT] I and II Trials) of a putative neuroprotectant. Early CT changes were graded using the Alberta Stroke Program Early CT Score (ASPECTS). Post–tissue plasminogen activator symptomatic intracerebral hemorrhage was defined as a worsening in National Institutes of Health Stroke Scale of ≥4 points within 36 hours with evidence of hemorrhage on follow-up neuroimaging. Good clinical outcome was defined as a modified Rankin scale of 0 to 2 at 90 days.</p> <p><b>Results:</b> Symptomatic intracerebral hemorrhage occurred in 5.6% of 965 patients treated with tissue plasminogen activator. In multivariable analysis, symptomatic intracerebral hemorrhage was increased with baseline antiplatelet use (single antiplatelet: OR, 2.04, 95% CI, 1.07 to 3.87, P=0.03; double antiplatelet: OR, 9.29, 3.28 to 26.32, P<0.001), higher National Institutes of Health Stroke Scale score (OR, 1.09 per point, 1.03 to 1.15, P=0.002), and CT changes defined by ASPECTS (ASPECTS 8 to 9: OR, 2.26, 0.63 to 8.10, P=0.21; ASPECTS ≤7: OR, 5.63, 1.66 to 19.10, P=0.006). Higher National Institutes of Health Stroke Scale was associated with decreased odds of good clinical outcome (OR, 0.82 per point, 0.79 to 0.85, P<0.001). There was no relationship between baseline antiplatelet use or CT changes and clinical outcome.</p> <p><b>Conclusions:</b> Along with higher National Institutes of Health Stroke Scale and extensive early CT changes, baseline antiplatelet use (particularly double antiplatelet therapy) was associated with an increased risk of post–tissue plasminogen activator symptomatic intracerebral hemorrhage. Of these factors, only National Institutes of Health Stroke Scale was associated with clinical outcome.</p&gt

Gene duplication in bovine brain myelin proteolipid and homology with related proteins

AbstractAnalysis of the amino acid sequence of bovine brain myelin proteolipid reveals not only extensive internal homology, but also homology with portions of the myelin basic protein, the peripheral nerve myelin protein, Po, and with the small proteolipid subunit of mitochondrial ATP synthase. These results suggest that the myelin proteolipid gene has been constructed from a small number of genetic elements, and that these elements are also found in non-myelin proteins. Furthermore, the proteolipid appears to have evolved by acquisition of elements from a ‘gene pool’ over a period of time, rather than by a simple duplication mechanism

Limits on τ lepton-flavor violating decays into three charged leptons

A search for the neutrinoless, lepton-flavor violating decay of the τ lepton into three charged leptons has been performed using an integrated luminosity of 468  fb^(-1) collected with the BABAR detector at the PEP-II collider. In all six decay modes considered, the numbers of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range (1.8–3.3)×10^(-8) at 90% confidence level

Measurement of the γγ^*→η_c transition form factor

We study the reaction e^+e^-→e^+e^-η_c, η_c→K_SK^±π^∓ and obtain η_c mass and width values 2982.2±0.4±1.6  MeV/c^2 and 31.7±1.2±0.8  MeV, respectively. We find Γ(η_c→γγ)B(ηc→KK π)=0.374±0.009±0.031  keV, and measure the γγ^*→η_c transition form factor in the momentum transfer range from 2 to 50  GeV^2. The analysis is based on 469  fb^(-1) of integrated luminosity collected at PEP-II with the BABAR detector at e^+e^- center-of-mass energies near 10.6 GeV

Nodal superconducting gap structure in the quasi-one-dimensional Cs2_2Cr3_3As3_3 investigated using μ\muSR measurements

The superconducting ground state of the newly discovered superconductor Cs$_2$Cr$_3$As$_3$ with a quasi-one-dimensional crystal structure ($T_{\bf c}\sim$ 2.1(1) K) has been investigated using magnetization and muon-spin relaxation or rotation ($\mu$SR), both zero-field (ZF) and transverse-field (TF), measurements. Our ZF $\mu$SR measurements reveal the presence of spin fluctuations below 4 K and the ZF relaxation rate ($\lambda$) shows enhancement below $T_{\bf c}\sim$ 2.1 K, which might indicate that the superconducting state is unconventional. This observation suggests that the electrons are paired via unconventional channels such as spin fluctuations, as proposed on the basis of theoretical models. Our analysis of the TF $\mu$SR results shows that the temperature dependence of the superfluid density is fitted better with a nodal gap structure than an isotropic s-wave model for the superconducting gap. The observation of a nodal gap in Cs$_2$Cr$_3$As$_3$ is consistent with that observed in the isostructural K$_2$Cr$_3$As$_3$ compound through TF $\mu$SR measurements. Furthermore, from our TF $\mu$SR study we have estimated the magnetic penetration depth $\lambda_{\mathrm{L}}$$(0)$ = 954 nm, superconducting carrier density $n_s = 4.98 \times 10^{26}~$m$^{-3}$, and carrier's effective-mass enhancement $m^*$ = 1.61m$_{e}$.Comment: 7 pages, 4 figures. arXiv admin note: substantial text overlap with arXiv:1505.0574

Measurement of the semileptonic branching fraction of the B_s meson

We report a measurement of the inclusive semileptonic branching fraction of the B_s meson using data collected with the BABAR detector in the center-of-mass energy region above the Υ(4S) resonance. We use the inclusive yield of ϕ mesons and the ϕ yield in association with a high-momentum lepton to perform a simultaneous measurement of the semileptonic branching fraction and the production rate of B_s mesons relative to all B mesons as a function of center-of-mass energy. The inclusive semileptonic branching fraction of the B_s meson is determined to be B(B_s→ℓνX)=9.5_(-2.0)^(+2.5)(stat)_(-1.9)^(+1.1)(syst)%, where ℓ indicates the average of e and μ

Study of Y(3S,2S) → ηY(1S) and Y(3S,2S) → π^+π^-Y(1S) hadronic transitions

We study the Υ(3S,2S)→ηΥ(1S) and Υ(3S,2S)→π^+π^-Υ(1S) transitions with 122×10^6Υ(3S) and 100×10^6Υ(2S) mesons collected by the BABAR detector at the PEP-II asymmetric-energy e^+e^- collider. We measure B[Υ(2S)→ηΥ(1S)]=(2.39±0.31(stat.)±0.14(syst.))×10^(-4) and Γ[Υ(2S)→ηΥ(1S)]/Γ[Υ(2S)→π^+π^-Υ(1S)]=(1.35±0.17(stat.)±0.08(syst.))×10^(-3). We find no evidence for Υ(3S)→ηΥ(1S) and obtain B[Υ(3S)→ηΥ(1S)]<1.0×10^(-4) and Γ[Υ(3S)→ηΥ(1S)]/ Γ[Υ(3S)→π^+π^-Υ(1S)]<2.3×10^(-3) as upper limits at the 90% confidence level. We also provide improved measurements of the Υ(2S)-Υ(1S) and Υ(3S)-Υ(1S) mass differences, 562.170±0.007(stat.)±0.088(syst.)  MeV/c^2 and 893.813±0.015(stat.)±0.107(syst.)  MeV/c^2, respectively