4,742 research outputs found

    Carotenoids - Effective Radical Scavengers for Healthy and Beautiful Skin

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    Free radicals are involved in various diseases and skin aging. To reduce and prevent this risk, our body produces antioxidants that can neutralize free radicals. However, some antioxidants need to be taken up with food, so a balanced and varied diet is essential for human health and beauty, along with sufficient exercise. Vegetables, especially curly kale, show very good antioxidative capacity due to the presence of carotenoids. As the recommended daily intake of vegetables is usually not consumed, dietary supplements are a good possibility to ingest carotenoids in a controlled and natural way. The positive effect of carotenoid-based dietary supplements on the skin has already been shown in several studies on healthy volunteers. Innovative non-invasive measuring methods have shown that oil extracts from vegetables significantly reduce not only free radicals in the skin but also the age-related breakdown of collagen and have a positive effect on skin parameters such as wrinkle volume. Thus, a balanced mixture of different natural carotenoids contributes to maintaining health and beauty

    Degenerate Four Virtual Soliton Resonance for KP-II

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    By using disipative version of the second and the third members of AKNS hierarchy, a new method to solve 2+1 dimensional Kadomtsev-Petviashvili (KP-II) equation is proposed. We show that dissipative solitons (dissipatons) of those members give rise to the real solitons of KP-II. From the Hirota bilinear form of the SL(2,R) AKNS flows, we formulate a new bilinear representation for KP-II, by which, one and two soliton solutions are constructed and the resonance character of their mutual interactions is studied. By our bilinear form, we first time created four virtual soliton resonance solution for KP-II and established relations of it with degenerate four-soliton solution in the Hirota-Satsuma bilinear form for KP-II.Comment: 10 pages, 5 figures, Talk on International Conference Nonlinear Physics. Theory and Experiment. III, 24 June-3 July, 2004, Gallipoli(Lecce), Ital

    Single gene mutation in a plant MYB transcription factor causes a major shift in pollinator preference.

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    Understanding the molecular basis of reproductive isolation and speciation is a key goal of evolutionary genetics. In the South American genus Petunia, the R2R3-MYB transcription factor MYB-FL regulates the biosynthesis of UV-absorbing flavonol pigments, a major determinant of pollinator preference. MYB-FL is highly expressed in the hawkmoth-pollinated P. axillaris, but independent losses of its activity in sister taxa P. secreta and P. exserta led to UV-reflective flowers and associated pollinator shifts in each lineage (bees and hummingbirds, respectively). We created a myb-fl CRISPR mutant in P. axillaris and studied the effect of this single gene on innate pollinator preference. The mutation strongly reduced the expression of the two key flavonol-related biosynthetic genes but only affected the expression of few other genes. The mutant flowers were UV reflective as expected but additionally contained low levels of visible anthocyanin pigments. Hawkmoths strongly preferred the wild-type P. axillaris over the myb-fl mutant, whereas both social and solitary bee preference depended on the level of visible color of the mutants. MYB-FL, with its specific expression pattern, small number of target genes, and key position at the nexus of flavonol and anthocyanin biosynthetic pathways, provides a striking example of evolution by single mutations of large phenotypic effect

    Anti-self-dual Riemannian metrics without Killing vectors, can they be realized on K3?

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    Explicit Riemannian metrics with Euclidean signature and anti-self dual curvature that do not admit any Killing vectors are presented. The metric and the Riemann curvature scalars are homogenous functions of degree zero in a single real potential and its derivatives. The solution for the potential is a sum of exponential functions which suggests that for the choice of a suitable domain of coordinates and parameters it can be the metric on a compact manifold. Then, by the theorem of Hitchin, it could be a class of metrics on K3K3, or on surfaces whose universal covering is K3K3.Comment: Misprints in eqs.(9-11) corrected. Submitted to Classical and Quantum Gravit

    Next-generation crossover-free quantum Hall arrays with superconducting interconnections

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    This work presents precision measurements of quantized Hall array resistance devices using superconducting, crossover-free and multiple interconnections as well as graphene split contacts. These new techniques successfully eliminate the accumulation of internal resistances and leakage currents that typically occur at interconnections and crossing leads between interconnected devices. As a result, a scalable quantized Hall resistance array is obtained with a nominal value that is as precise and stable as that from single-element quantized Hall resistance standards

    Red- and Near-Infrared-Excited Autofluorescence as a Marker for Acute Oxidative Stress in Skin Exposed to Cigarette Smoke Ex Vivo and In Vivo

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    Air pollution is increasing worldwide and skin is exposed to high levels of pollution daily, causing oxidative stress and other negative consequences. The methods used to determine oxidative stress in the skin are invasive and non-invasive label-free in vivo methods, which are severely limited. Here, a non-invasive and label-free method to determine the effect of cigarette smoke (CS) exposure on skin ex vivo (porcine) and in vivo (human) was established. The method is based on the measurement of significant CS-exposure-induced enhancement in red- and near-infrared (NIR)-excited autofluorescence (AF) intensities in the skin. To understand the origin of red- and NIR-excited skin AF, the skin was exposed to several doses of CS in a smoking chamber. UVA irradiation was used as a positive control of oxidative stress in the skin. The skin was measured with confocal Raman microspectroscopy before CS exposure, immediately after CS exposure, and after skin cleaning. CS exposure significantly increased the intensity of red- and NIR-excited skin AF in a dose-dependent manner in the epidermis, as confirmed by laser scanning microscopy AF imaging and fluorescence spectroscopy measurements. UVA irradiation enhanced the intensity of AF, but to a lower extent than CS exposure. We concluded that the increase in red- and NIR-excited AF intensities of the skin after CS exposure could clearly be related to the induction of oxidative stress in skin, where skin surface lipids are mainly oxidized

    Classification of integrable Volterra type lattices on the sphere. Isotropic case

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    The symmetry approach is used for classification of integrable isotropic vector Volterra lattices on the sphere. The list of integrable lattices consists mainly of new equations. Their symplectic structure and associated PDE of vector NLS-type are discussed.Comment: 16 page

    Solutions of the sDiff(2)Toda equation with SU(2) Symmetry

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    We present the general solution to the Plebanski equation for an H-space that admits Killing vectors for an entire SU(2) of symmetries, which is therefore also the general solution of the sDiff(2)Toda equation that allows these symmetries. Desiring these solutions as a bridge toward the future for yet more general solutions of the sDiff(2)Toda equation, we generalize the earlier work of Olivier, on the Atiyah-Hitchin metric, and re-formulate work of Babich and Korotkin, and Tod, on the Bianchi IX approach to a metric with an SU(2) of symmetries. We also give careful delineations of the conformal transformations required to ensure that a metric of Bianchi IX type has zero Ricci tensor, so that it is a self-dual, vacuum solution of the complex-valued version of Einstein's equations, as appropriate for the original Plebanski equation.Comment: 27 page
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