201 research outputs found

    Anisotropic Lifshitz Point at O(ϔL2)O(\epsilon_L^2)

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    We present the critical exponents ÎœL2\nu_{L2}, ηL2\eta_{L2} and ÎłL\gamma_{L} for an mm-axial Lifshitz point at second order in an Ï”L\epsilon_{L} expansion. We introduced a constraint involving the loop momenta along the mm-dimensional subspace in order to perform two- and three-loop integrals. The results are valid in the range 0≀m<d0 \leq m < d. The case m=0m=0 corresponds to the usual Ising-like critical behavior.Comment: 10 pages, Revte

    Specific heat amplitude ratios for anisotropic Lifshitz critical behaviors

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    We determine the specific heat amplitude ratio near a mm-axial Lifshitz point and show its universal character. Using a recent renormalization group picture along with new field-theoretical Ï”L\epsilon_{L}-expansion techniques, we established this amplitude ratio at one-loop order. We estimate the numerical value of this amplitude ratio for m=1m=1 and d=3d=3. The result is in very good agreement with its experimental measurement on the magnetic material MnPMnP. It is shown that in the limit m→0m \to 0 it trivially reduces to the Ising-like amplitude ratio.Comment: 8 pages, RevTex, accepted as a Brief Report in Physical Review

    Quantum scattering in one dimension

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    A self-contained discussion of nonrelativistic quantum scattering is presented in the case of central potentials in one space dimension, which will facilitate the understanding of the more complex scattering theory in two and three dimensions. The present discussion illustrates in a simple way the concept of partial-wave decomposition, phase shift, optical theorem and effective-range expansion.Comment: 8 page

    Susceptibility amplitude ratio for generic competing systems

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    We calculate the susceptibility amplitude ratio near a generic higher character Lifshitz point up to one-loop order. We employ a renormalization group treatment with LL independent scaling transformations associated to the various inequivalent subspaces in the anisotropic case in order to compute the ratio above and below the critical temperature and demonstrate its universality. Furthermore, the isotropic results with only one type of competition axes have also been shown to be universal. We describe how the simpler situations of mm-axial Lifshitz points as well as ordinary (noncompeting) systems can be retrieved from the present framework.Comment: 20 pages, no figure

    Immunization With The Maebl M2 Domain Protects Against Lethal Plasmodium Yoelii Infection.

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    Malaria remains a world-threatening disease largely because of the lack of a long-lasting and fully effective vaccine. MAEBL is a type 1 transmembrane molecule with a chimeric cysteine-rich ectodomain homologous to regions of the Duffy binding-like erythrocyte binding protein and apical membrane antigen 1 (AMA1) antigens. Although MAEBL does not appear to be essential for the survival of blood-stage forms, ectodomains M1 and M2, homologous to AMA1, seem to be involved in parasite attachment to erythrocytes, especially M2. MAEBL is necessary for sporozoite infection of mosquito salivary glands and is expressed in liver stages. Here, the Plasmodium yoelii MAEBL-M2 domain was expressed in a prokaryotic vector. C57BL/6J mice were immunized with doses of P. yoelii recombinant protein rPyM2-MAEBL. High levels of antibodies, with balanced IgG1 and IgG2c subclasses, were achieved. rPyM2-MAEBL antisera were capable of recognizing the native antigen. Anti-MAEBL antibodies recognized different MAEBL fragments expressed in CHO cells, showing stronger IgM and IgG responses to the M2 domain and repeat region, respectively. After a challenge with P. yoelii YM (lethal strain)-infected erythrocytes (IE), up to 90% of the immunized animals survived and a reduction of parasitemia was observed. Moreover, splenocytes harvested from immunized animals proliferated in a dose-dependent manner in the presence of rPyM2-MAEBL. Protection was highly dependent on CD4(+), but not CD8(+), T cells toward Th1. rPyM2-MAEBL antisera were also able to significantly inhibit parasite development, as observed in ex vivo P. yoelii erythrocyte invasion assays. Collectively, these findings support the use of MAEBL as a vaccine candidate and open perspectives to understand the mechanisms involved in protection.833781-379

    Use of ergogenic aids among Brazilian athletes: a cross-sectional study exploring competitive level, sex and sports

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    Was investigated ergogenic aids (EAs) used by Brazilian athletes and their association with performance, sex, sports classification, and modality. It identified the main purposes of EAs and their prescription.Methods239 athletes of 15 modalities, ranging from regional to international level, answered a survey online.ResultsHighly competitive athletes consumed nutritional and mechanical aids more (OR = 1.96 CI 95% [1.28–2.9]; OR = 1.79 CI 95% [1.29–2.47]), while the use of psychological EAs decreased [OR = 1.66 95% CI (1.18–2.94); p = 0.001]. Male athletes [OR = 1.44 CI 95% (1.11–2.88)] and individual sports practitioners [OR = 1.78 CI 95% (1.02–3.11)] used nutritional aids more. Triathlon athletes had higher nutritional EA use, while soccer athletes had lower. Combat sports athletes had higher pharmacological EA use.ConclusionAthletes use nutritional and pharmacological aids more to improve performance and gain lean body mass. Mechanical aids were used for recovery and psychological aids for motivation. Self-prescription is common, especially for pharmacological aids

    UVA and UVB formulation phototoxicity in a three-dimensional human skin model: photodegradation effect

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    In vitro three-dimensional human skin models are an innovative alternative to evaluate cytotoxicity and phototoxicity in the cosmetic industry. The aim of this study was to use a skin model to evaluate the potential toxicity of sunscreen formulations with or without exposure to UV radiation. In addition, the toxicity of these formulations was evaluated after exposure to photodegradation. The results showed toxicity with all formulations/conditions tested, including the control formulation, compared to PBS. Cell viability of photodegraded formulations - prior to the phototoxicity radiation process - was higher, indicating that some formulation components were degraded into products with reduced toxicity. The results also indicated that avobenzone was more unstable/toxic than octyl p-methoxycinnamate under the same test conditions. The sunscreens and their formulations were shown to be toxic to skin model cells to some extent, even when not exposed to UV irradiation; however the biological role of this toxicity is unclear. This result shows the importance of testing sunscreen formulations in real in-use conditions. Finally, since we used an in vitro assay based on a human cell model, this non-invasive technique represents a suitable alternative to animal models for phototoxicity tests in general and could have application in screening new sunscreen products
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