Characterization, cloning and immunogenicity of antigens released by lung-stage larvae of Schistosoma mansoni

Lung-stage schistosomula are the target of protective immunity in mice vaccinated with attenuated cercariae of Schistosoma mansoni. Therefore, proteins present at this developmental stage, and in particular those which are secreted, are a potential source of novel vaccine candidates. However, little information is available about such molecules. Here we describe the cDNA clones identified by screening expression libraries with serum raised against proteins released by lung-stage schistosomula. In total, 11 different cDNA species were identified, 6 of which have been described previously in S. mansoni; these included fructose 1,6-bisphosphate aldolase and Sm21.7 which together accounted for two-thirds of all positive clones. Of the 5 newly described schistosome genes, 1 cDNA had a high degree of homology to the s5a subunit of 26S proteasomes, most significant being with the human protein. The remaining 4 clones showed no significant homologies to any genes sequenced previously. Fructose 1,6-bisphosphate aldolase, Sm21.7, the proteasome homologue and 1 unknown clone (A26) have been expressed in a bacterial expression system and serum produced against each recombinant protein. Immunolocalization showed fructose 1,6-bisphosphate aldolase, Sm21.7 and the proteasome homologue to be most abundant in muscle cells whilst clone A26 was distributed throughout many tissues, but was most abundant in the tegument. Analysis of the cellular immune responses of vaccinated mice showed 3 of the 4 expressed clones to be highly immunogenic, inducing the secretion of large quantities of the Th1-type cytokine interferon gamma

Phonons in graphene with point defects

The phonon density of states (DOS) of graphene with different types of point defects (carbon isotopes, substitution atoms, vacancies) is considered. Using a solvable model which is based on the harmonic approximation and the assumption that the elastic forces act only between nearest neighboring ions we calculate corrections to graphene DOS dependent on type and concentration of defects. In particular the correction due to isotopic dimers is determined. It is shown that a relatively small concentration of defects may lead to significant and specific changes in the DOS, especially at low frequencies, near the Van Hove points and in the vicinity of the K-points of the Brillouin zone. In some cases defects generate one or several narrow gaps near the critical points of the phonon DOS as well as resonance states in the Brillouin zone regular points. All types of defects are characterized by the appearance of one or more additional Van Hove peaks near the (Dirac) K points and their singular contribution may be comparable with the effect of electron-phonon interaction. Besides, for low frequencies and near the critical points the relative change in density of states may be many times higher than the concentration of defects.Comment: 19 pages, 7 figure

Measuring molecular abundances in comet C/2014 Q2 (Lovejoy) using the APEX telescope

Comet composition provides critical information on the chemical and physical processes that took place during the formation of the Solar system. We report here on millimetre spectroscopic observations of the long-period bright comet C/2014 Q2 (Lovejoy) using the Atacama Pathfinder Experiment (APEX) band 1 receiver between 2015 January UT 16.948 to 18.120, when the comet was at heliocentric distance of 1.30 AU and geocentric distance of 0.53 AU. Bright comets allow for sensitive observations of gaseous volatiles that sublimate in their coma. These observations allowed us to detect HCN, CH3OH (multiple transitions), H2CO and CO, and to measure precise molecular production rates. Additionally, sensitive upper limits were derived on the complex molecules acetaldehyde (CH3CHO) and formamide (NH2CHO) based on the average of the strongest lines in the targeted spectral range to improve the signal-to-noise ratio. Gas production rates are derived using a non-LTE molecular excitation calculation involving collisions with H2O and radiative pumping that becomes important in the outer coma due to solar radiation. We find a depletion of CO in C/2014 Q2 (Lovejoy) with a production rate relative to water of 2 per cent, and relatively low abundances of Q(HCN)/Q(H2O), 0.1 per cent, and Q(H2CO)/Q(H2O), 0.2 per cent. In contrast the CH3OH relative abundance Q(CH3OH)/Q(H2O), 2.2 per cent, is close to the mean value observed in other comets. The measured production rates are consistent with values derived for this object from other facilities at similar wavelengths taking into account the difference in the fields of view. Based on the observed mixing ratios of organic molecules in four bright comets including C/2014 Q2, we find some support for atom addition reactions on cold dust being the origin of some of the molecules.Comment: 10 pages, 7 figures, to be published in MNRA

Magnetic properties of 3d-impurities substituted in GaAs

We have calculated the magnetic properties of substituted 3d-impurities (Cr-Ni) in a GaAs host by means of first principles electronic structure calculations. We provide a novel model explaining the ferromagnetic long rang order of III-V dilute magnetic semiconductors. The origin of the ferromagnetism is shown to be due to delocalized spin-uncompensated As dangling bond electrons. Besides the quantitative prediction of the magnetic moments, our model provides an understanding of the halfmetallicity, and the raise of the critical temperature with the impurity concentration

Sub-millimeter images of a dusty Kuiper belt around eta Corvi

We present sub-millimeter and mid-infrared images of the circumstellar disk around the nearby F2V star eta Corvi. The disk is resolved at 850um with a size of ~100AU. At 450um the emission is found to be extended at all position angles, with significant elongation along a position angle of 130+-10deg; at the highest resolution (9.3") this emission is resolved into two peaks which are to within the uncertainties offset symmetrically from the star at 100AU projected separation. Modeling the appearance of emission from a narrow ring in the sub-mm images shows the observed structure cannot be caused by an edge-on or face-on axisymmetric ring; the observations are consistent with a ring of radius 150+-20AU seen at 45+-25deg inclination. More face-on orientations are possible if the dust distribution includes two clumps similar to Vega; we show how such a clumpy structure could arise from the migration over 25Myr of a Neptune mass planet from 80-105AU. The inner 100AU of the system appears relatively empty of sub-mm emitting dust, indicating that this region may have been cleared by the formation of planets, but the disk emission spectrum shows that IRAS detected an additional hot component with a characteristic temperature of 370+-60K (implying a distance of 1-2AU). At 11.9um we found the emission to be unresolved with no background sources which could be contaminating the fluxes measured by IRAS. The age of this star is estimated to be ~1Gyr. It is very unusual for such an old main sequence star to exhibit significant mid-IR emission. The proximity of this source makes it a perfect candidate for further study from optical to mm wavelengths to determine the distribution of its dust.Comment: 22 pages, 4 figures. Scheduled for publication in ApJ 10 February 2005 issu

Applying theories of health behaviour and change to hearing health research: time for a new approach

Objective: In recent years, there has been an increase in the application of behavioural models, such as social cognition models, to the promotion of hearing health. Despite this, there exists a well-developed body of literature that suggests such models may fail to consistently explain reliable amounts of variability in human behaviours. Design: This paper provides a summary of this research across selected models of health-related behaviour, outlining the current state of the evidence. Results: Recent work in the field of behaviour change is presented together with commentary on the design and reporting of behaviour change interventions. Conclusions: We propose that attempts to use unreliable models to explain and predict hearing health behaviours should now be replaced by work which integrates the latest in behaviour change science, such as the Behaviour Change Wheel and Theoretical Domains Framework

Polarization forces in water deduced from single molecule data

Intermolecular polarization interactions in water are determined using a minimal atomic multipole model constructed with distributed polarizabilities. Hydrogen bonding and other properties of water-water interactions are reproduced to fine detail by only three multipoles $\mu_H$, $\mu_O$, and $\theta_O$ and two polarizabilities $\alpha_O$ and $\alpha_H$, which characterize a single water molecule and are deduced from single molecule data.Comment: 4 revtex pages, 3 embedded color PS figure

Ab initio calculations of the hydrogen bond

Recent x-ray Compton scattering experiments in ice have provided useful information about the quantum nature of the interaction between H$_2$O monomers. The hydrogen bond is characterized by a certain amount of charge transfer which could be determined in a Compton experiment. We use ab-initio simulations to investigate the hydrogen bond in H$_2$O structures by calculating the Compton profile and related quantities in three different systems, namely the water dimer, a cluster containing 12 water molecules and the ice crystal. We show how to extract estimates of the charge transfer from the Compton profiles.Comment: 16 pages, 7 figures, to appear in Phys. Rev.

GRIDKIT: Pluggable overlay networks for Grid computing

A `second generation' approach to the provision of Grid middleware is now emerging which is built on service-oriented architecture and web services standards and technologies. However, advanced Grid applications have significant demands that are not addressed by present-day web services platforms. As one prime example, current platforms do not support the rich diversity of communication `interaction types' that are demanded by advanced applications (e.g. publish-subscribe, media streaming, peer-to-peer interaction). In the paper we describe the Gridkit middleware which augments the basic service-oriented architecture to address this particular deficiency. We particularly focus on the communications infrastructure support required to support multiple interaction types in a unified, principled and extensible manner-which we present in terms of the novel concept of pluggable overlay networks