582 research outputs found
Immune Responses in Human Necatoriasis: Association between Interleukin-5 Responses and Resistance to Reinfection
Cytokine and proliferative responses to Necator americanus infection were measured in a treatment-reinfection study of infected subjects from an area of Papua New Guinea where N. americanus is highly endemic. Before treatment, most subjects produced detectable interleukin (IL)4 (97%), IL-5 (86%), and interferon (IFN)-Îł(64%) in response to adult N. americanus antigen. Pretreatment IFN-Îł responses were negatively associated with hookworm burden, decreasing by 18 pg/mL for each increase of 1000 eggs/gram (epg) (n = 75; P < .01). Mean IFN-Îł responses increased significantly after anthelmintic treatment, from 166 to 322 pg/mL (n = 42; P < .01). The intensity of reinfection was significantly negatively correlated with pretreatment IL-5 responses, decreasing by 551 epg for each 100 pg/mL increase in production of IL-5 (n = 51; P < .01). These data indicate that there is a mixed cytokine response in necatoriasis, with worm burdenassociated suppression of IFN-Îł responses to adult N. americanus antigen. Resistance to reinfection is associated with the parasite-specific IL-5 response
Localization of Quantum States at the Cyclotron Resonance
A new type of localization - localization over the quantum resonance cells -
in an intrinsically degenerate system is explored by using the quasienergy
eigenstates.Comment: 6 pages of Latex, 6 figure
Differential expression of glutathione S-transferase (GST) by adult Heligmosomoides polygyrus during primary infection in fast and slow responding hosts
Successful vaccination of BALB/c mice against human hookworm (Necator americanus): the immunological phenotype of the protective response
In this murine (BALB/c) model of necatoriasis, high levels of protection against challenge infection by Necator americanus larvae (n = 300) were afforded by successive vaccinations at 14-day intervals, either subcutaneously or percutaneously, with Îł-irradiated N. americanus larvae (n = 300). Percutaneous vaccination was significantly more effective than the subcutaneous route, with pulmonary larval burdens at 3 days post-infection being reduced by 97.8% vs. 89.3%, respectively, after three immunisations (p < 0.05). No worms were recovered from the intestines of thrice vaccinated mice. Two percutaneous vaccinations also reduced worm burdens, by 57% in the lungs and 98% in the intestines; p < 0.05. In vaccinated animals, lung pathology (mainly haemorrhage) following infection was greatly reduced compared with non-vaccinated animals. In vaccinated mice (but not in non-vaccinated mice) mast cells accumulated in the skin and were degranulated. RT-PCR analyses of mRNAs in the skin of vaccinated animals indicated increased expression of IL-4 relative to Îł-IFN. Lymphocytes from the axillary (skin-draining) lymph nodes of vaccinated mice, stimulated in vitro with concanavalin A, exhibited enhanced secretion of IL-4 protein and a higher Il-4/Îł-IFN protein ratio than lymphocytes from non-vaccinated animals. In vaccinated mice, levels of IgG1 and IgG3 (directed against larval excretory/secretory products) were elevated for the most part compared with those in non-vaccinated animals. These data demonstrate the successful vaccination of BALB/c mice against human hookworm infection and suggest that a localised Th2 response may be important for conferring protection against necatoriasis
Evaporation of Sunscreen Films: How the UV Protection Properties Change
© 2016 American Chemical Society. We have investigated the evaporation of thin sunscreen films and how the light absorption and the derived sun protection factor (SPF) change. For films consisting of solutions of common UV filters in propylene glycol (PG) as solvent, we show how evaporation generally causes three effects. First, the film area can decrease by dewetting leading to a transient increase in the average film thickness. Second, the film thins by evaporative loss of the solvent. Third, precipitation of the UV filter occurs when solvent loss causes the solubility limit to be reached. These evaporation-induced changes cause the UV absorbance of the film to decrease with resultant loss of SPF over the time scale of the evaporation. We derive an approximate model which accounts semiquantitatively for the variation of SPF with evaporation. Experimental results for solutions of different UV filters on quartz, different skin mimicking substrates, films with added nanoparticles, films with an added polymer and films with fast-evaporating decane as solvent (instead of slow evaporating PG) are discussed and compared with model calculations. Addition of either nanoparticles or polymer suppress film dewetting. Overall, it is hoped that the understanding gained about the mechanisms whereby film evaporation affects the SPF will provide useful guidance for the formulation of more effective sunscreens
A gobal fit to the anomalous magnetic moment, b->s gamma and Higgs limits in the constrained MSSM
New data on the anomalous magnetic moment a_mu of the muon together with the
b->s gamma decay rate are considered within the supergravity inspired
constrained minimal supersymmetric model. We perform a global statistical chi^2
analysis of these data and show that the allowed region of parameter space is
bounded from below by the Higgs limit, which depends on the trilinear coupling
and from above by the anomalous magnetic moment a_mu. The newest b->s gamma
data deviate 1.7 sigma from recent SM calculations and prefer a similar
parameter region as the 2.6 sigma deviation from a_mu.Comment: 12 pages, 7 figs. Refs. update
A variational approach to the QCD wave functional:Dynamical mass generation and confinement
We perform a variational calculation in the SU(N) Yang Mills theory in 3+1
dimensions. Our trial variational states are explicitly gauge invariant, and
reduce to simple Gaussian states in the zero coupling limit. Our main result is
that the energy is minimized for the value of the variational parameter away
form the perturbative value. The best variational state is therefore
characterized by a dynamically generated mass scale . This scale is related
to the perturbative scale by the following relation:
. Taking the one loop QCD -
function and we find (for N=3) the vacuum condensate
.Comment: 37 pages, (1 Figure available upon request), preprint LA-UR-94-2727,
PUPT-149
A pulsating white dwarf in an eclipsing binary
White dwarfs are the burnt-out cores of Sun-like stars and are the fate of 97 per cent of the stars in our Galaxy. The internal structure and composition of white dwarfs are hidden by their high gravities, which causes all elements apart from the lightest ones to settle out of their atmospheres. The most direct method of probing the inner structure of stars and white dwarfs in detail is via asteroseismology. Here we present a pulsating white dwarf in an eclipsing binary system, enabling us to place extremely precise constraints on the mass and radius of the white dwarf from the lightcurve, independent of the pulsations. This 0.325-solar-mass white dwarf—one member of the SDSS J115219.99+024814.4 system—will serve as a powerful benchmark with which to constrain empirically the core composition of low-mass stellar remnants and to investigate the effects of close binary evolution on the internal structure of white dwarfs
Urban geology of Swansea: Neath : Port Talbot
The conurbation of Swansea–Neath–Port Talbot is one of the main centres of
industrial development in South Wales. A long history of mineral extraction and
processing, which stoked the initial growth of the towns, declined during the 20th
Century. Many of these former industries have left a legacy of groundwater, watercourse
and land contamination.
A project funded by the Environment & Hazards Directorate (British Geological
Survey) between 2000-2005 used available geological data to determine potential
areas of contaminated land and understand the influence of the geology to pollutant
pathways (Waters et al., In press a). The study covered 100 km2 of the Swansea-
Neath-Port Talbot area (Fig. 2.1) and was aimed at providing data relevant to
contaminated land issues, to augment the study by Arup (1997) on earth science
information relevant to planning and development for the Swansea-Llanelli district,
and look at new methodologies of presenting the data
Is null-point reconnection important for solar flux emergence?
The role of null-point reconnection in a 3D numerical MHD model of solar
emerging flux is investigated. The model consists of a twisted magnetic flux
tube rising through a stratified convection zone and atmosphere to interact and
reconnect with a horizontal overlying magnetic field in the atmosphere. Null
points appear as the reconnection begins and persist throughout the rest of the
emergence, where they can be found mostly in the model photosphere and
transition region, forming two loose clusters on either side of the emerging
flux tube. Up to 26 nulls are present at any one time, and tracking in time
shows that there is a total of 305 overall, despite the initial simplicity of
the magnetic field configuration. We find evidence for the reality of the nulls
in terms of their methods of creation and destruction, their balance of signs,
their long lifetimes, and their geometrical stability. We then show that due to
the low parallel electric fields associated with the nulls, null-point
reconnection is not the main type of magnetic reconnection involved in the
interaction of the newly emerged flux with the overlying field. However, the
large number of nulls implies that the topological structure of the magnetic
field must be very complex and the importance of reconnection along separators
or separatrix surfaces for flux emergence cannot be ruled out.Comment: 26 pages, 12 figures. Added one referenc
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