612 research outputs found
Resveratrol protects SR-B1 levels in keratinocytes exposed to cigarette smoke
No full textCigarette smoking (CS) has been strongly linked to several health conditions including heart disease, lung cancer, and other respiratory and circulatory ailments. Deleterious effects of cigarette smoking on skin have also been well documented, but unlike effects on other organs, damage does not depend upon inhalation. The upper layer of the skin, the stratum corneum (rich in cholesterol fatty acids and ceramide), is very susceptible to damage induced by exposure to environmental stressors that can modify its lipid composition and thereby affect its function of protecting skin from dehydration. Scavenger receptor B1 (SR-B1) is involved in the uptake of cholesterol in several tissues including skin. We previously demonstrated that CS exposure induces formation of aldehyde (HNE) adducts that decrease SR-B1 expression. As topical resveratrol, a well-known polyphenolic stilbene, has been demonstrated to show benefits against skin disorders, we investigated its possible role as a protective agent against CS-induced reduction of SR-B1 expression in cutaneous tissue. In this study, we demonstrate that resveratrol at doses ranging from 0.5 to 10 μM is not toxic and is able to increase SR-B1 protein levels in a dose-dependent manner in human keratinocytes. Moreover, when the cells that were pretreated with various doses of resveratrol were exposed to CS, the loss of SR-B1 was prevented in a dose-dependent manner. In addition, in keratinocytes, resveratrol was also able to prevent an increase in HNE-protein adducts induced by CS. In particular resveratrol was able to prevent HNE-SR-B1 adduct formation. Thus, resveratrol seems to be a natural compound that could provide skin with a defense against exogenous stressors by protecting the essential cholesterol receptor, SR-B1
CANONICAL ABERRATION THEORY IN ELECTROMAGNETIC MULTIPOLES
No full textIn a 2N-pole electromagnetic system, defining the electron optical Hamiltonian function, we have derived both general algebraic expressions (arbitrary N) and special numerical formulas (N = 3,4,5,6,7) for different aberrations from lower to higher order (i.e., the order of N - 1, N + 1, 2N - 3, 2N - 1, 3N - 5). The so-called canonical aberration theory in electromagnetic multipoles has thus been developed, which allows us to deduce angular dependencies of different aberrations and to examine the possibility for spherical correction of a round lens by using multipoles.Physics, AppliedSCI(E)0ARTICLE125968-59756
Tunable visual color filter using microfluidic grating
No full textAuthor name used in this publication: X. M. Zhang2010-2011 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishedVoR allowe
Comparative effects between electronic and cigarette smoke in human keratinocytes and epithelial lung cells
No full textInformation about the harmful effects of vaping is sparse and inconsistent, therefore, since the use of electronic cigarettes (e-CIGs) has become increasingly popular as a tool to limit tobacco smoking, it is urgent to establish the toxicity of the commercial e-CIGs. Skin (HaCaT) and lung (A549) cells, the main targets of cigarette smoke (CS), were exposed to e-CIG
vapor and CS using an in vitro system. The cytotoxic effect of the exposure was analyzed in both cell types by ultrastructural morphology, Trypan Blue exclusion test and LDH assay. In addition, pro-inflammatory cytokines were measured by the Bio-Plex assay. The cytotoxic components of e-CIG were restrained to the flavoring compound and, to a lesser extent,
to nicotine although their effects were less harmful to that of CS. Humectants alone exhibited no cytotoxicity but induced the release of cytokines and pro-inflammatory mediators. Based on our results, we can state that exposure to e-CIG vapors results in far less toxic than exposure to CS. In fact, besides the deleterious effect of flavor and nicotine, even the humectants alone are able to evocate cytokines release. This study will hopefully promote the development of safer e-CIGs to help people quit smoking
Bivariate Tensor-Product B-Splines in a Partly Linear Model
No full textAbstractIn some applications, the mean or median response is linearly related to some variables but the relation to additional variables are not easily parameterized. Partly linear models arise naturally in such circumstances. Suppose that a random sample {(Ti, Xi, Yi),i=1, 2, …, n} is modeled byYi=XTiβ0+g0(Ti)+errori, whereYiis a real-valued response,Xi∈RpandTiranges over a unit square, andg0is an unknown function with a certain degree of smoothness. We make use of bivariate tensor-product B-splines as an approximation of the functiong0and consider M-type regression splines by minimization of ∑ni=1ρ(Yi−XTiβ−gn(Ti)) for some convex functionρ. Mean, median and quantile regressions are included in this class. We show under appropriate conditions that the parameter estimate ofβachieves its information bound asymptotically and the function estimate ofg0attains the optimal rate of convergence in mean squared error. Our asymptotic results generalize directly to higher dimensions (for the variableT) provided that the functiong0is sufficiently smooth. Such smoothness conditions have often been assumed in the literature, but they impose practical limitations for the application of multivariate tensor product splines in function estimation. We also discuss the implementation of B-spline approximations based on commonly used knot selection criteria together with a simulation study of both mean and median regressions of partly linear models
Dendrolycopodium verticale comb. nov (Lycopodiopsida: Lycopodiaceae) from China
No full textA new combination in the lycophyte genus Dendrolycopodium (Lycopodiacae) from Lycopodium, D. verticale (Li Bing Zhang) Li Bing Zhang & X. M. Zhou, for a Chinese species is made
Theoretical interpretation on ion heating experiments in reverse field pinch devices
No full textA new set of equations for the energies of the mean magnetic field and the mean plasma velocity is derived taking the dynamo effects into account, by which the anomalous phenomenon, T(i) > T(e), observed in some reversed field pinches (RFP's) is successfully explained
Interference effect on friction behavior of asperities on single crystal copper
No full textBy using Green function molecular dynamics method, we systematically study the friction behavior of a single asperity and asperity array over the (1 1 1) surface of single crystal copper. We find that internal plastic behavior (burst of stacking faults, dislocation emission and propagation) is a promising reason for the higher value of static friction coefficient than that of dynamics friction in non-adhesive scratch. For the rough surface, however, the difference between static and dynamic friction coefficients disappear due to the interference between asperities. The interference dramatically increases the friction coefficient by introducing atomic scale plastic features (pile-up atoms, stacking faults, and U-shape dislocation loop). (C) 2014 Elsevier Ltd. All rights reserved
Los contextos sociales e institucionales de una economía monástica: Santa María de Montederramo en el siglo XIII
No full textEditada en la Fundación Empresa PúblicaLa autora se pregunta por las causas de la consolidación y pervivencia
de formas institucionales ineficientes desde un punto de vista económico. Se
estudia un caso concreto: el monasterio cisterciense de Santa María de Montederramo
(Orense) en el siglo XIII para poner en evidencia la existencia de
marcos institucionales formales e informales definidores de la acción de unos
agentes cuyos intereses se construyeron en el proceso de interacción social,
es decir, en contextos socio-culturales determinados y no como fruto de la
limitación institucional sobre la naturaleza maximizadora de agentes extemporales.
En primer lugar, el artículo presenta las paradojas en los debates
clásicos sobre el Císter. Atendiendo a la Regla de la Orden, se acepta que
el Císter perseguía varios objetivos: la compactación de las parcelas adquiridas,
la tenencia en régimen de propiedad no compartida y la explotación de la
tierra con mano de obra propia. A partir del caso elegido se reflexiona sobre
la distancia entre los principios teóricos de la Orden y la morfología diversa
de los señoríos y sus formas de gestión práctica. Se concluye que los monasterios
se convirtieron en aparatos acumuladores de bienes invirtiendo recursos
según criterios de reciprocidad, redistribución, identidad y estableciendo redes
con las comunidades o con algunos de sus miembros destacados. En este
compacto entramado de dinámicas sociales y mentales se fueron configurando
sus formas económicas.The author searches into the reasons for the perpetuation in inefficient
institutions. The monastery in Sta. María de Montederramo (Orense, Galicia)
in the 13th century lets to underline the existence of formal and informal
institutions defíning agents' cholees whose interests are building up in the
process of social interaction. Moreover those interests emerge within
socio-cultural context, rather than as the outcome of the institutional
constreints over a given nature as profit maximazers. The article reviews the
classical debate about the Cister. Given the Rule of the Order it is argued
that Cistercians pursued the organization of coherent territorial estates,
exclusive property rights over the land and own labour force. Working on
the case-study, the gap between the theoretical principie of the Order and
the specif management and contractual agreements about land tenancy are
considered. The conclusion puts forward that monasteries were devices of
accumulation because they developed practices of reciprocity, redistribution
and identity within the peasant communities and through the organization
of personal and social networks with some of the outstanding members of
the local community. In the tied web of social and cultural dynamics, the
economic patterns were hammered out.Publicad
The Number of Parts of Given Multiplicity in a Random Integer Partition
No full text2000 Mathematics Subject Classification: 05A16, 05A17.Let Xm,n denote the number of parts of multiplicity m in a random partition of the positive integer n. We study the asymptotic behaviour of the variance of Xm,n as n → ∞ and fixed m.The author was supported by the *MRTN-CT-2004-511953* project carried out by Alfred Renyi Institute of Mathematics, in the framework of the European Community's Structuring the European Research Area programme. This paper is also partially supported by NFSI-Bulgaria, Grant No VU-MI-105/2005
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