5,572 research outputs found
A dose-dependent plasma signature of the safety and immunogenicity of the rVSV-Ebola vaccine in Europe and Africa.
The 2014-2015 Ebola epidemic affected several African countries, claiming more than 11,000 lives and leaving thousands with ongoing sequelae. Safe and effective vaccines could prevent or limit future outbreaks. The recombinant vesicular stomatitis virus-vectored Zaire Ebola (rVSV-ZEBOV) vaccine has shown marked immunogenicity and efficacy in humans but is reactogenic at higher doses. To understand its effects, we examined plasma samples from 115 healthy volunteers from Geneva who received low-dose (LD) or high-dose (HD) vaccine or placebo. Fifteen plasma chemokines/cytokines were assessed at baseline and on days 1, 2 to 3, and 7 after injection. Significant increases in monocyte-mediated MCP-1/CCL2, MIP-1β/CCL4, IL-6, TNF-α, IL-1Ra, and IL-10 occurred on day 1. A signature explaining 68% of cytokine/chemokine vaccine-response variability was identified. Its score was higher in HD versus LD vaccinees and was associated positively with vaccine viremia and negatively with cytopenia. It was higher in vaccinees with injection-site pain, fever, myalgia, chills, and headache; higher scores reflected increasing severity. In contrast, HD vaccinees who subsequently developed arthritis had lower day 1 scores than other HD vaccinees. Vaccine dose did not influence the signature despite its influence on specific outcomes. The Geneva-derived signature associated strongly (ρ = 0.97) with that of a cohort of 75 vaccinees from a parallel trial in Lambaréné, Gabon. Its score in Geneva HD vaccinees with subsequent arthritis was significantly lower than that in Lambaréné HD vaccinees, none of whom experienced arthritis. This signature, which reveals monocytes' critical role in rVSV-ZEBOV immunogenicity and safety across doses and continents, should prove useful in assessments of other vaccines
Strongly correlated s-wave pairing in the n-type infinite-layer cuprate
Quasiparticle tunneling spectra of the electron-doped (n-type) infinite-layer
cuprate Sr_{0.9}La_{0.1}CuO_2 reveal characteristics that counter a number of
common phenomena in the hole-doped (p-type) cuprates. The optimally doped
Sr_{0.9}La_{0.1}CuO_2 with T_c = 43 K exhibits a momentum-independent
superconducting gap \Delta = 13.0 +- 1.0 meV that substantially exceeds the BCS
value, and the spectral characteristics indicate insignificant quasiparticle
damping by spin fluctuations and the absence of pseudogap. The response to
quantum impurities in the Cu-sites also differs fundamentally from that of the
p-type cuprates with d_{x^2-y^2}-wave pairing symmetry.Comment: 4 pages, 3 figures. Published in Physical Review Letter.
Corresponding author: Nai-Chang Yeh (e-mail: [email protected]
Magnetic Phase Diagram of GdNi2B2C: Two-ion Magnetoelasticity and Anisotropic Exchange Couplings
Extensive magnetization and magnetostriction measurements were carried out on
a single crystal of GdNi2B2C along the main tetragonal axes. Within the
paramagnetic phase, the magnetic and strain susceptibilities revealed a weak
anisotropy in the exchange couplings and two-ion tetragonal-preserving
alpha-strain modes. Within the ordered phase, magnetization and
magnetostriction revealed a relatively strong orthorhombic distortion mode and
rich field-temperature phase diagrams. For H//(100) phase diagram, three
field-induced transformations were observed, namely, at: Hd(T), related to the
domain alignment; Hr(T), associated with reorientation of the moment towards
the c-axis; and Hs(T), defining the saturation process wherein the exchange
field is completely counterbalanced. On the other hand, For H//(001) phase
diagram, only two field-induced transformations were observed, namely at: Hr(T)
and Hs(T). For both phase diagrams, Hs(T) follows the relation
Hs[1-(T/Tn)^2]^(1/2)kOe with Hs(T-->0)=128.5(5) kOe and Tn(H=0)=19.5 K. In
contrast, the thermal evolution of Hr(T) along the c-axis (much simpler than
along the a-axis) follows the relation Hr[1-T/Tr]^(1/3) kOe where
Hr(T-->0)=33.5(5) kOe and Tr(H=0)=13.5 K. It is emphasized that the
magnetoelastic interaction and the anisotropic exchange coupling are important
perturbations and therefore should be explicitly considered if a complete
analysis of the magnetic properties of the borocarbides is desired
Precautionary advice about mobile phones: Public understandings and intended responses
The official published version can be obtained from the link below - Copyright @ Taylor & FrancisThere is a widespread academic and policy debate about public responses to precaution in public health campaigns. This paper explores these issues in relation to the precautionary stance adopted in the UK around the regulation of mobile telecommunications. The aim of the paper is to examine the nature of attitudes to precaution, and the way in which these, along with other relevant variables, relate to the intention to adopt relevant behaviours. The results from an experimental study (n = 173) indicate that people distinguish between two dimensions of precaution: firstly in relation to its value or necessity per se and secondly as anchored to notions of governance. The two variables differentially relate to other variables including trust and uncertainty, and are predictive of intended behaviour change indirectly, through worry about mobile phone risks. Precautionary advice was generally interpreted as causing concern rather than providing reassurance. The results suggest that precaution may be considered a valuable stance but this does not mean that it is seen as good governance or that it will reduce concern. Whilst the discourse of precaution is aimed at reducing concern, it appears that the uptake of relevant behaviours is largely triggered by worry
Petahertz Spintronics
The enigmatic coupling between electronic and magnetic phenomena was one of
the riddles propelling the development of modern electromagnetism. Today, the
fully controlled electric field evolution of ultrashort laser pulses permits
the direct and ultrafast control of electronic properties of matter and is the
cornerstone of light-wave electronics. In sharp contrast, because there is no
first order interaction between light and spins, the magnetic properties of
matter can only be affected indirectly on the much slower tens-of-femtosecond
timescale in a sequence of optical excitation followed by the rearrangement of
the spin structure. Here we record an orders of magnitude faster magnetic
switching with sub-femtosecond response time by initiating optical excitations
with near-single-cycle laser pulses in a ferromagnetic layer stack. The
unfolding dynamics are tracked in real-time by a novel attosecond time-resolved
magnetic circular dichroism (atto-MCD) detection scheme revealing optically
induced spin and orbital momentum transfer (OISTR) in synchrony with light
field driven charge relocation. In tandem with ab-initio quantum dynamical
modelling, we show how this mechanism provides simultaneous control over
electronic and magnetic properties that are at the heart of spintronic
functionality. This first incarnation of attomagnetism observes light field
coherent control of spin-dynamics in the initial non-dissipative temporal
regime and paves the way towards coherent spintronic applications with
Petahertz clock rates.Comment: 12 pages, 3+1 figure
R-values in Low Energy e^+e^- Annihilation
This presentation briefly summarizes the recent measurements of R-values in
low energy e^+e^- annihilation. The new experiments aimed at reducing the
uncertainties in R-values and performed with the upgraded Beijing Spectrometer
(BESII) at Beijing Electron Positron Collider (BEPC) in Beijing and with CMD-2
and SND at VEEP-2M in Novosibirsk are reviewed and discussed.Comment: 17 pages, 10 figures, invited presentation at the XIX International
Symposium on Lepton and Photon Interactions at High Energy, Stanford
University, August 199
Electronic Structure of Ladder Cuprates
We study the electronic structure of the ladder compounds (SrCa)CuO 14-24-41
and SrCuO 123. LDA calculations for both give similar Cu 3d-bands near the
Fermi energy. The hopping parameters estimated by fitting LDA energy bands show
a strong anisotropy between the t_perp t_par intra-ladder hopping and small
inter-ladder hopping. A downfolding method shows that this anisotropy arises
from the ladder structure.The conductivity perpendicular to the ladders is
computed assuming incoherent tunneling giving a value close to experiment.Comment: 5 pages, 3 figure
Influence of age, social patterns and nasopharyngeal carriage on antibodies to three conserved pneumococcal surface proteins (PhtD, PcpA and PrtA) in healthy young children
The acquisition of specific antibodies is paramount to protect children against pneumococcal diseases, and a better understanding of how age, ethnicity and/or Streptococcus pneumoniae (Spn) nasopharyngeal carriage influence the acquisition of antibodies to pneumococcal surface proteins (PSP) is important for the development of novel serodiagnostic and immunisation strategies. IgG antibody titres against three conserved PSP (PhtD, PcpA and PrtA) in the sera of 451 healthy children aged 1 to 24months from Israel [Jewish (50.1%) and Bedouin (49.9%)] were measured by enzyme-linked immunosorbent assay (ELISA), while nasopharyngeal swabs from these children were assessed for the presence of Spn. Globally, anti-PhtD and anti-PrtA geometric mean concentrations (GMC; EU/ml) were high at <2.5months of age [PhtD: 35.3, 95% confidence interval (CI) 30.6-40.6; PrtA: 71.2, 95 % CI 60-84.5], was lower at 5-7months of age (PhtD: 10, 95 % CI 8-12.4; PrtA: 17.9, 95 % CI 14.4-22.1) and only increased after 11months of age. In contrast, an increase in anti-PcpA was observed at 5-7months of age. Anti-PcpA and anti-PrtA, but not anti-PhtD, were significantly higher in Bedouin children (PcpA: 361.6 vs. 226.3, p = 0.02; PrtA: 67.2 vs. 29.5, p < 0.001) in whom Spn nasopharyngeal carriage was identified earlier (60% vs. 38% of carriers <6months of age, p = 0.002). Spn carriage was associated with significantly higher anti-PSP concentrations in carriers than in non-carriers (p < 0.001 for each PSP). Thus, age, ethnicity and, essentially, nasopharyngeal carriage exert distinct cumulative influences on infant responses to PSP. These specific characteristics are worthwhile to include in the evaluation of pneumococcal seroresponses and the development of new PSP-based vaccine
Anisotropy of the Mobility of Pentacene from Frustration
The bandstructure of pentacene is calculated using first-principles density
functional theory. A large anisotropy of the hole and electron effective masses
within the molecular planes is found. The band dispersion of the HOMO and the
LUMO is analyzed with the help of a tight-binding fit. The anisotropy is shown
to be intimately related to the herringbone structure.Comment: Accepted for publication in Synthetic Metal
Left bundle branch block causes relative but not absolute septal underperfusion during exercise
Aims Left bundle branch block (LBBB) often causes septal perfusion defects in radionuclide myocardial perfusion imaging using exercise (Ex) but rarely using vasodilator stress. We studied whether this is due to an underlying structural disease inherent to spontaneous LBBB or whether it is also found in temporary LBBB induced by right ventricular pacing (PM) indicating a functional rather than a structural alteration. Methods and results Regional myocardial blood flow (MBF) at rest and at Ex was measured with(15)O-H(2)O and PET in 10 age-matched healthy volunteers (controls), 10 LBBB patients and 10 PM patients with right ventricular pacing off and on (PM off and PM on). Although at Ex septal MBF tended to be higher in LBBB than in controls (3.04 +/- 1.18 vs. 2.27 +/- 0.72 mL/min/g; P= ns), the ratio septal/lateral MBF was 19% lower in LBBB than in controls (P < 0.05). Similarly, switching PM on at Ex decreased the ratio septal/lateral MBF by 17% (P < 0.005). Conclusion The apparent septal perfusion defect in LBBB is mainly due to a relative lateral hyperperfusion rather than to an absolute septal flow decrease. This pattern seems to be reversibly inducible by right ventricular pacing, suggesting a functional rather than a structural alteratio
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