541 research outputs found

    The immunological analysis of epitopes on hCG

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    The heterodimeric glycoprotein hormone, human chorionic gonadotropin, has been extensively characterized in terms of its recognition by mouse monoclonal antibodies. A number of different approaches have led to the definition of several epitope clusters on the surface of the molecule. These include epitopes located solely on the alpha- or beta-chain, some of which are masked when the two chains associate to form the holo-hormone. Additional epitopes comprise amino acids contributed by both the chains. In contrast to the extensive knowledge regarding B cell epitopes, the characterization of T cell epitopes on hCG has only recently begun to be explored

    Pattern formation in crystal growth under parabolic shear flow

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    Morphological instability of the solid-liquid interface occuring in a crystal growing from an undercooled thin liquid being bounded on one side by a free surface and flowing down inclined plane is investigated by a linear stability analysis under shear flow. It is found that restoring forces due to gravity and surface tension is important factor for stabilization of the solid-liquid interface on long length scales. This is a new stabilizing effect different from the Gibbs-Thomson effect. A particular long wavelength mode of about 1 cm of wavy pattern observed on the surface of icicles covered with thin layer of flowing water is obtained from the dispersion relation including the effect of flow and restoring forces.Comment: 30 pages, 4 figure

    Bi2Te3Bi_2Te_3: Implications of the rhombohedral k-space texture on the evaluation of the in-plane/out-of-plane conductivity anisotropy

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    Different computational scheme for calculating surface integrals in anisotropic Brillouin zones are compared. The example of the transport distribution function (plasma frequency) of the thermoelectric Material \BiTe near the band edges will be discussed. The layered structure of the material together with the rhombohedral symmetry causes a strong anisotropy of the transport distribution function for the directions in the basal (in-plane) and perpendicular to the basal plane (out-of-plane). It is shown that a thorough reciprocal space integration is necessary to reproduce the in-plane/out-of-plane anisotropy. A quantitative comparison can be made at the band edges, where the transport anisotropy is given in terms of the anisotropic mass tensor.Comment: 7 pages, 6 figs., subm. to J. Phys. Cond. Ma

    The relationship between blood lead, blood pressure, stroke, and heart attacks in middle-aged British men.

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    The relationship between blood lead concentration and blood pressure is examined in a survey of 7371 men aged 40 to 59 from 24 British towns. After allowance for relevant confounding variables, including town of residence and alcohol consumption, there exists a very weak but statistically significant positive association between blood lead and both systolic and diastolic blood pressure. These cross-sectional data indicate that an estimated mean increase of 1.45 mm Hg in systolic blood pressure occurs for every doubling of blood lead concentration with a 95% confidence interval of 0.47 to 2.43 mm Hg. After 6 years of follow-up, 316 of these men had major ischemic heart disease, and 66 had a stroke. After allowance for the confounding effects of cigarette smoking and town of residence there is no evidence that blood lead is a risk factor for these cardiovascular events. However, as the blood lead-blood pressure association is so weak, it is unlikely that any consequent association between lead and cardiovascular disease could be demonstrated from prospective epidemiological studies. An overview of data from this and other large epidemiological surveys provides reasonably consistent evidence on lead and blood pressure. While NHANES II data on 2254 U.S. men indicate a slightly stronger association between blood lead and systolic blood pressure, data from two Welsh studies on over 2000 men did not show a statistically significant association. However, the overlapping confidence limits for all these studies suggest that there may be a weak positive statistical association whereby systolic blood pressure is increased by about 1 mm Hg for every doubling of blood lead concentration.(ABSTRACT TRUNCATED AT 250 WORDS

    Approximate action-angle variables for the figure-eight and other periodic three-body orbits

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    We use the maximally permutation symmetric set of three-body coordinates, that consist of the "hyper-radius" R=ρ2+λ2R = \sqrt{\rho^{2} + \lambda^{2}}, the "rescaled area of the triangle" 32R2ρ×λ\frac{\sqrt 3}{2 R^2} |{\bm \rho} \times {\bm \lambda}|) and the (braiding) hyper-angle ϕ=arctan(2ρλλ2ρ2)\phi = \arctan(\frac{2{\bm \rho} \cdot {\bm \lambda}}{\lambda^2 - \rho^2}), to analyze the "figure-eight" choreographic three-body motion discovered by Moore \cite{Moore1993} in the Newtonian three-body problem. Here ρ,λ{\bm \rho}, {\bm \lambda} are the two Jacobi relative coordinate vectors. We show that the periodicity of this motion is closely related to the braiding hyper-angle ϕ\phi. We construct an approximate integral of motion Gˉ{\bar{G}} that together with the hyper-angle ϕ\phi forms the action-angle pair of variables for this problem and show that it is the underlying cause of figure-eight motion's stability. We construct figure-eight orbits in two other attractive permutation-symmetric three-body potentials. We compare the figure-eight orbits in these three potentials and discuss their generic features, as well as their differences. We apply these variables to two new periodic, but non-choreographic orbits: One has a continuously rising ϕ\phi in time tt, just like the figure-eight motion, but with a different, more complex periodicity, whereas the other one has an oscillating ϕ(t)\phi(t) temporal behavior.Comment: 11 pages, 19 figure

    The Nernst effect and the boundaries of the Fermi liquid picture

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    Following the observation of an anomalous Nernst signal in cuprates, the Nernst effect was explored in a variety of metals and superconductors during the past few years. This paper reviews the results obtained during this exploration, focusing on the Nernst response of normal quasi-particles as opposed to the one generated by superconducting vortices or by short-lived Cooper pairs. Contrary to what has been often assumed, the so-called Sondheimer cancelation does not imply a negligible Nernst response in a Fermi liquid. In fact, the amplitude of the Nernst response measured in various metals in the low-temperature limit is scattered over six orders of magnitude. According to the data, this amplitude is roughly set by the ratio of electron mobility to Fermi energy in agreement with the implications of the semi-classical transport theory.Comment: Final version, Topical review for JPC

    Investigation of factors influencing the immunogenicity of hCG as a potential cancer vaccine

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    Human hCG and its β‐subunit (hCGβ) are tumour autocrine growth factors whose presence in the serum of cancer patients has been linked to poorer prognosis. Previous studies have shown that vaccines, which target these molecules and/or the 37 amino acid C‐terminal hCGβ peptide (hCGβCTP), induce antibody responses in a majority of human recipients. Here we explored whether the immunogenicity of vaccines containing an hCGβ mutant (hCGβR68E, designed to eliminate cross‐reactivity with luteinizing hormone) or hCGβCTP could be enhanced by coupling the immunogen to different carriers (KLH or Hsp70) using different cross‐linkers (EDC or GAD) and formulated with different adjuvants (RIBI or Montanide ISA720). While there was little to choose between KLH and Hsp70 as carriers, their influence on the effectiveness of a vaccine containing the BAChCGβR68E mutant was less marked, presumably because being a foreign species, this mutant protein itself might provide T‐helper epitopes. The mutant provided a significantly better vaccine than the hCGβCTP peptide irrespective of the carrier used, how it was cross‐linked to the carrier or which adjuvant was used when hCG was the target. Nonetheless, for use in humans where hCG is a tolerated self‐protein, the need for a carrier is of fundamental importance. Highest antibody titres were obtained by linking the BAChCGβR68E to Hsp70 as a carrier by GAD and using RIBI as the adjuvant, which also resulted in antibodies with significantly higher affinity than those elicited by hCGβCTP peptide vaccine. This makes this mutant vaccine a promising candidate for therapeutic studies in hCGβ‐positive cancer patients

    Optimal interlayer hopping and high temperature Bose–Einstein condensation of local pairs in quasi 2D superconductors

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    Both FeSe and cuprate superconductors are quasi 2D materials with high transition temperatures and local fermion pairs. Motivated by such systems, we investigate real space pairing of fermions in an anisotropic lattice model with intersite attraction, V, and strong local Coulomb repulsion, U, leading to a determination of the optimal conditions for superconductivity from Bose–Einstein condensation. Our aim is to gain insight as to why high temperature superconductors tend to be quasi 2D. We make both analytically and numerically exact solutions for two body local pairing applicable to intermediate and strong V. We find that the Bose–Einstein condensation temperature of such local pairs pairs is maximal when hopping between layers is intermediate relative to in-plane hopping, indicating that the quasi 2D nature of unconventional superconductors has an important contribution to their high transition temperatures

    Neutron-3H and Proton-3He Zero Energy Scattering

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    The Kohn variational principle and the (correlated) Hyperspherical Harmonics technique are applied to study the n-3H and p-3He scattering at zero energy. Predictions for the singlet and triplet scattering lengths are obtained for non-relativistic nuclear Hamiltonians including two- and three-body potentials. The calculated n-3H total cross section agrees well with the measured value, while some small discrepancy is found for the coherent scattering length. For the p-3He channel, the calculated scattering lengths are in reasonable agreement with the values extrapolated from the measurements made above 1 MeV.Comment: 13 pages, REVTEX, 1 figur

    Comment on ``Large-space shell-model calculations for light nuclei''

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    In a recent publication Zheng, Vary, and Barrett reproduced the negative quadrupole moment of Li-6 and the low-lying positive-parity states of He-5 by using a no-core shell model. In this Comment we question the meaning of these results by pointing out that the model used is inadequate for the reproduction of these properties.Comment: Latex with Revtex, 1 postscript figure in separate fil
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