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A consideration of the mycotoxin hypothesis with special reference to the mycoflora of maize, sorghum, wheat and groundnuts (G105)
This review attempts to trace the connection between the mycology of foodstuffs and the onset of disease due to the toxins that various fungi produce within those foodstuffs. The association of fungal activity with the occurrence of various disease syndromes in man and animals has only recently been recognised. Possibly this is because the epidemiology of mycotoxins involves more than one scientific discipline. and the collation of knowledge has inevitably been slow. Also the chronic long term effects of mycotoxin poisoning may have been obviated by better preventive measures in the developed countries; certainly it is the Third World countries which have contributed most to our understanding of this subject. Because of the relative remoteness of these areas from the main areas of research however, it has taken longer to collect sufficient data, especially that pertaining to the human situation
Extraction of aqueous gold sols with styrene/2-vinylpyridine block copolymers in toluene
Polymers containing small noble-metal particles are of interest for catalysis and in the generation of optically tunable composites. The currently used process results in materials which are often difficult to process. A method is presented here for the direct transfer of small gold particles from an aqueous sol into a non-aqueous polymer solution (e.g. a block copolymer, see Figure) facilitating the formation of films
Response of human engineered cartilage based on articular or nasal chondrocytes to interleukin-1? and low oxygen
Previous studies showed that human nasal chondrocytes (HNC) exhibit higher proliferation and chondrogenic capacity as compared to human articular chondrocytes (HAC). To consider HNC as a relevant alternative cell source for the repair of articular cartilage defects it is necessary to test how these cells react when exposed to environmental factors typical of an injured joint. We thus aimed this study at investigating the responses of HNC and HAC to exposure to interleukin (IL)-1? and low oxygen. For this purpose HAC and HNC harvested from the same donors (N=5) were expanded in vitro and then cultured in pellets or collagen-based scaffolds at standard (19%) or low oxygen (5%) conditions. Resulting tissues were analyzed after a short (3 days) exposure to IL-1?, mimicking the initially inflammatory implantation site, or following a recovery time (1 or 2 weeks for pellets and scaffolds, respectively). After IL-1? treatment, constructs generated by both HAC and HNC displayed a transient loss of GAG (up to 21.8% and 36.8%, respectively) and, consistently, an increased production of metalloproteases (MMP)-1 and -13. Collagen type II and the cryptic fragment of aggrecan (DIPEN), both evaluated immunohistochemically, displayed a trend consistent with GAG and MMPs production. HNC-based constructs exhibited a more efficient recovery upon IL-1? withdrawal, resulting in a higher accumulation of GAG (up to 2.6-fold) compared to the corresponding HAC-based tissues. On the other hand, HAC displayed a positive response to low oxygen culture, while HNC were only slightly affected by oxygen percentage. Collectively, under the conditions tested mimicking the postsurgery articular environment, HNC retained a tissue-forming capacity, similar or even better than HAC. These results represent a step forward in validating HNC as a cell source for cartilage tissue engineering strategies
Prompt atmospheric neutrinos and muons: dependence on the gluon distribution function
We compute the next-to-leading order QCD predictions for the vertical flux of
atmospheric muons and neutrinos from decays of charmed particles, for different
PDF's (MRS-R1, MRS-R2, CTEQ-4M and MRST) and different extrapolations of these
at small partonic momentum fraction x. We find that the predicted fluxes vary
up to almost two orders of magnitude at the largest energies studied, depending
on the chosen extrapolation of the PDF's. We show that the spectral index of
the atmospheric leptonic fluxes depends linearly on the slope of the gluon
distribution function at very small x. This suggests the possibility of
obtaining some bounds on this slope in ``neutrino telescopes'', at values of x
not reachable at colliders, provided the spectral index of atmospheric leptonic
fluxes could be determined.Comment: 20 pages including 8 figure
Effect of nuclear periphery on nucleon transfer in peripheral collisions
A comparison of experimental heavy residue cross sections from the reactions
86Kr+64Ni,112,124Sn with the model of deep-inelastic transfer (DIT) is carried
out. A modified expression for nucleon transfer probabilities is used at
non-overlapping projectile-target configurations, introducing a dependence on
isospin asymmetry at the nuclear periphery. The experimental yields of
neutron-rich nuclei close to the projectile are reproduced better and the trend
deviating from the bulk isospin equilibration is explained. For the
neutron-rich products further from the projectile, originating from hot
quasiprojectiles, the statistical multifragmentation model reproduces the mass
distributions better than the model of sequential binary decay. In the reaction
with proton-rich target 112Sn the nucleon exchange appears to depend on isospin
asymmetry of nuclear periphery only when surface separation is larger than 0.8
fm due to the stronger Coulomb interaction at more compact di-nuclear
configuration.Comment: LaTeX, 13 pages, 7 figures, to appear in Nuclear Physics
Sensitivity on Earth Core and Mantle densities using Atmospheric Neutrinos
Neutrino radiography may provide an alternative tool to study the very deep
structures of the Earth. Though these measurements are unable to resolve the
fine density layer features, nevertheless the information which can be obtained
are independent and complementary to the more conventional seismic studies. The
aim of this paper is to assess how well the core and mantle averaged densities
can be reconstructed through atmospheric neutrino radiography. We find that
about a 2% sensitivity for the mantle and 5% for the core could be achieved for
a ten year data taking at an underwater km^3 Neutrino Telescope. This result
does not take into account systematics related to the details of the
experimental apparatus.Comment: 11 pages, 11 figures, accepted for publication in JCA
Characterizing precursors to stellar clusters with Herschel
Context. Despite their profound effect on the universe, the formation of massive stars and stellar clusters remains elusive. Recent advances in observing facilities and computing power have brought us closer to understanding this formation process. In the past decade, compelling evidence has emerged that suggests infrared dark clouds (IRDCs) may be precursors to stellar clusters. However, the usual method for identifying IRDCs is biased by the requirement that they are seen in absorption against background mid-IR emission, whereas dust continuum observations allow cold, dense pre-stellar-clusters to be identified anywhere. Aims: We aim to understand what dust temperatures and column densities characterize and distinguish IRDCs, to explore the population of dust continuum sources that are not IRDCs, and to roughly characterize the level of star formation activity in these dust continuum sources. Methods: We use Hi-GAL 70 to 500 m bright sources at the warmest. Finally, we identify five candidate IRDC-like sources on the far-side of the Galaxy. These are cold (20 K), high column density (N(H) gt 10 cm) clouds identified with Hi-GAL which, despite bright surrounding mid-IR emission, show little to no absorption at 8 $m. These are the first inner Galaxy far-side candidate IRDCs of which the authors are aware. Herschel in an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation by NASA.The FITS files discussed in the paper would be released publicly WITH the Hi-GAL data (on the Hi-GAL website) when the Hi-GAL data is released publicly.Peer reviewe
Sea quark polarization and semi-inclusive DIS data
We investigate the potential impact of forthcoming Jefferson Lab
semi-inclusive polarized deep inelastic scattering proton measurements in the
determination of the sea quark polarization in the nucleon by means of a next
to leading order global QCD analysis. Specifically, we estimate the resulting
improvement in the constraints on polarized parton densities for the different
flavors, which is found to be significant for up and strange quarks, and the
correlation between remaining uncertainty ranges for each of the parton
species.Comment: 7 pages, 4 figures. Version to be published in the European Physical
Journal
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