Constraints on Minute-Scale Transient Astrophysical Neutrino Sources

High-energy neutrino emission has been predicted for several short-lived astrophysical transients including gamma-ray bursts (GRBs), core-collapse supernovae with choked jets, and neutron star mergers. IceCube's optical and x-ray follow-up program searches for such transient sources by looking for two or more muon neutrino candidates in directional coincidence and arriving within 100 s. The measured rate of neutrino alerts is consistent with the expected rate of chance coincidences of atmospheric background events and no likely electromagnetic counterparts have been identified in Swift follow-up observations. Here, we calculate generic bounds on the neutrino flux of short-lived transient sources. Assuming an E^{-2.5} neutrino spectrum, we find that the neutrino flux of rare sources, like long gamma-ray bursts, is constrained to <5% of the detected astrophysical flux and the energy released in neutrinos (100 GeV to 10 PeV) by a median bright GRB-like source is <10^{52.5}  erg. For a harder E^{-2.13} neutrino spectrum up to 30% of the flux could be produced by GRBs and the allowed median source energy is <10^{52}  erg. A hypothetical population of transient sources has to be more common than 10^{-5}  Mpc^{-3}  yr^{-1} (5×10^{-8}  Mpc^{-3}  yr^{-1} for the E^{-2.13} spectrum) to account for the complete astrophysical neutrino flux.

Search for neutrinos from decaying dark matter with IceCube: IceCube Collaboration

With the observation of high-energy astrophysical neutrinos by the IceCube Neutrino Observatory, interest has risen in models of PeV-mass decaying dark matter particles to explain the observed flux. We present two dedicated experimental analyses to test this hypothesis. One analysis uses 6 years of IceCube data focusing on muon neutrino 'track' events from the Northern Hemisphere, while the second analysis uses 2 years of 'cascade' events from the full sky. Known background components and the hypothetical flux from unstable dark matter are fitted to the experimental data. Since no significant excess is observed in either analysis, lower limits on the lifetime of dark matter particles are derived: we obtain the strongest constraint to date, excluding lifetimes shorter than10 28 s at 90% CL for dark matter masses above 10 TeV .

Effect of glycosylated hemoglobin on response to ranibizumab therapy in diabetic macular edema: real-world outcomes in 312 patients

OBJECTIVE

To investigate the effect of serum glycosylated hemoglobin (HbA1c) on the outcomes of ranibizumab therapy for diabetic macular edema (DME).

DESIGN

Retrospective cohort study.

PARTICIPANTS

Patients receiving ranibizumab injections for centre-involving DME in a National Health Service setting.

METHODS

The Moorfields OpenEyes database was used to study eyes with DME treated with ranibizumab from October 2013 to November 2015 at the Moorfields City Road, Ealing, Northwick Park, and St George's Hospital sites. Only eyes receiving a minimum of 3 injections and completing 12 months of follow-up were included. If both eyes received treatment, the first eye treated was analyzed. When both eyes received initial treatment simultaneously, random number tables were used to select the eye for analysis. HbA1c was tested at the initiation of ranibizumab treatment. Multivariate regression analysis was used to identify relationships between HbA1c and the outcome measures.

OUTCOMES

The primary outcome was change in visual acuity (VA) Early Treatment of Diabetic Retinopathy study (ETDRS) letters. The secondary outcomes were change in central subfield thickness (CSFT) and macular volume (MV), as well as number of injections in year 1.

RESULTS

Three hundred and twelve eyes of 312 patients were included in the analysis. HbA1c was not related to change in VA (p = 0.577), change in CSFT (p = 0.099), change in MV (p = 0.082), or number of injections in year 1 (p = 0.859).

CONCLUSIONS

HbA1c is not related to functional or anatomical outcomes at 1 year in DME treated with ranibizumab.

Characterisation of the selective binding of antibiotics vancomycin and teicoplanin by the VanS receptor regulating type A vancomycin resistance in the enterococci

A-type resistance towards "last-line" glycopeptide antibiotic vancomycin in the leading hospital acquired infectious agent, the enterococci, is the most common in the UK. Resistance is regulated by the VanRASA two-component system, comprising the histidine sensor kinase VanSA and the partner response regulator VanRA. The nature of the activating ligand for VanSA has not been identified, therefore this work sought to identify and characterise ligand(s) for VanSA. In vitro approaches were used to screen the structural and activity effects of a range of potential ligands with purified VanSA protein. Of the screened ligands (glycopeptide antibiotics vancomycin and teicoplanin, and peptidoglycan components N-acetylmuramic acid, D-Ala-D-Ala and Ala-D-y-Glu-Lys-D-Ala-D-Ala) only glycopeptide antibiotics vancomycin and teicoplanin were found to bind VanSA with different affinities (vancomycin 70μM; teicoplanin 30 and 170μM), and were proposed to bind via exposed aromatic residues tryptophan and tyrosine. Furthermore, binding of the antibiotics induced quicker, longer-lived phosphorylation states for VanSA, proposing them as activators of type A vancomycin resistance in the enterococci.

Selective complexation of divalent cations by a cyclic α,β-peptoid hexamer: a spectroscopic and computational study

The first report on metal binding ability of a cyclic α,β-peptoid hexamer towards a selection of metal cations is presented.

Mycobacterium tuberculosis Sonicate-Induced IFNγ, CXCL10 and IL10 can Differentiate Severity in Tuberculosis

Improved tools are required to study immunopathogenesis of tuberculosis (TB). Mycobacterium tuberculosis antigen-stimulated T cell-based assays can detect TB but are less effective when responses are compromised such as in severe disease. We investigated immune responses to M. tuberculosis whole sonicate (MTBs), recombinant antigens ESAT6 and CFP10 in whole blood cells of healthy endemic controls (EC, n = 42) and patients with pulmonary (PTB, n = 36) or extrapulmonary (ETB, n = 41) disease. Biomarkers of T cell activation (IFNγ) or modulation (IL10) and chemokines, CXCL9, CXCL10 and CCL2, secretion were measured. MTBs, ESAT6 and CFP10 all induced IFNγ responses in TB. ESAT6-induced IFNγ was elevated in TB as compared with EC. MTBs stimulated the highest IFNγ levels but did not differentiate between TB and EC. However, MTBs-induced CXCL10 (P = 0.004) was reduced, while IL10 (P < 0.001) was raised in TB as compared with EC. Between sites, MTBs-induced CCL2 (P = 0.001) and IL10 secretion was higher in PTB than ETB (P < 0.001). In comparison of disease severity, MTBs-induced IFNγ (P = 0.014) and CXCL10 (P = 0.022) levels were raised in moderate as compared with far advanced PTB. In ETB, MTBs-induced IL10 levels were greater in less-severe (L-ETB) than in severe disseminated (D-ETB) cases, P = 0.035. Within the L-ETB group, MTBs-induced IFNγ was greater in patients with tuberculous lymphadenitis than those with pleural TB (P = 0.002). As immune responses to MTBs were differentially activated in TB of different sites and severity, we propose the utility of MTBs-induced IFNγ, CXCL10 and IL10 as biomarkers in TB.