454 research outputs found

    Determination of polycyclic aromatic hydrocarbons in lipstick by gas-chromatography coupled to mass spectrometry: A case history

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    A suitable extraction protocol based on an liquid-liquid extraction with hexane/dimethyl sulfoxide and a GC/MS method were developed and validated to determine the concentration of six prohibited Polycyclic Aromatic Hydrocarbons (PAHs; benzo[a]pyrene; dibenz[a,h]anthracene; benz[a]anthracene; benzo[j]fluoranthene; benzo[k]fluoranthene; chrysene) in lipsticks commissioned by a cosmetic company to a manufacturer. The lipsticks were produced in four different colors. Analyses confirmed the presence of benz[a]anthracene and chrysene only in two colors in a concentration of 9.3\u20139.4 ng/g. The concentration of PAHs was 250 times lower than what is considered a toxic level on the basis of what reported in the litaraure and guidances for cosmetic ingredients; therefore we could assume that the risk for consumer health was negligeble

    Domain wall brane in squared curvature gravity

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    We suggest a thick braneworld model in the squared curvature gravity theory. Despite the appearance of higher order derivatives, the localization of gravity and various bulk matter fields is shown to be possible. The existence of the normalizable gravitational zero mode indicates that our four-dimensional gravity is reproduced. In order to localize the chiral fermions on the brane, two types of coupling between the fermions and the brane forming scalar is introduced. The first coupling leads us to a Schr\"odinger equation with a volcano potential, and the other a P\"oschl-Teller potential. In both cases, the zero mode exists only for the left-hand fermions. Several massive KK states of the fermions can be trapped on the brane, either as resonant states or as bound states.Comment: 18 pages, 5 figures and 1 table, references added, improved version to be published in JHE

    Leishmania amazonensis downregulates macrophage iNOS expression via Histone Deacetylase 1 (HDAC1): a novel parasite evasion mechanism.

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    The induced expression of nitric oxide synthase (iNOS) controls the intracellular growth of Leishmania in infected macrophages. Histones deacetylases (HDACs) negatively regulate gene expression through the formation of complexes containing transcription factors such as NF-κB p50/50. Herein, we demonstrated the occupancy of p50/p50_HDAC1 to iNOS promoter associated with reduced levels of H3K9Ac. Remarkably, we found increased levels of HDAC1 in L. amazonensis-infected macrophages. HDAC1 upregulation was not found in L. major-infected macrophages. The parasite intracellular load was reduced in HDAC1 knocked-down macrophages, which presented increased nitric oxide levels. HDAC1 silencing led to the occupancy of CBP/p300 to iNOS promoter and the rise of H3K9Ac modification. Importantly, the immunostaining of skin samples from hiporeactive cutaneous leishmaniasis patients infected with L. amazonensis, revealed high levels of HDAC1. In brief, L. amazonensis induces HDAC1 in infected macrophages, which contribute to parasite survival and is associated to hiporeactive stage found in L. amazonensis infected patients

    Using ancient DNA to unravel taxonomic puzzles: the identity of Deuterodon pedri (Ostariophysi: Characidae)

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    ABSTRACT Accurate identification is essential for any study exploring biodiversity. Unfortunately, museum type specimens preserved for more than a hundred years are often not informative enough for precise identification of the species represented by the name-bearing type. The use of ancient DNA can help solve taxonomic problems when name-bearing types no longer have diagnostic morphological features that allow for an accurate identification of the species involved. That is the case for Deuterodon pedri, an endemic species from a small drainage in the rio Doce basin in Minas Gerais, Brazil, for which the type material is in poor condition. Specimens of D. pedri were collected in 1865 by the Thayer Expedition to Brazil and fixed in spirits, enabling them to yield viable DNA. As the morphology alone of the type material does not allow for an accurate identification, we used both morphological and ancient DNA (aDNA) methods to decisively establish the identity of D. pedri. This identification allowed us to recognize the species among recently collected specimens and then, based on them, redescribe the species. A genetype for the lectotype of D. pedri is presented
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