Estudio comparativo de la peinabilidad del cabello humano empleando distintos acondicionadores.

Un acondicionador es un agente químico que confiere al cabello dañado cierta elásticidad y peinabilidad independientemente de una mejor apariencia (brillo, etc.) suavidad y soltura. La eficacia objetiva de este tipo de cosméticos en cuanto a las propiedades tensiles puede verificarse por dinamometría. En este trabajo se determina la eficacia de cuatro acondicionadores comerciales distintos utilizando como criterio de evaluación la elasticidad, y carga para la rotura. Se mide también la peinabilidad empleando un dispositivo especial, en el dinamómetro que simula la operación de peinado. En conjunto se constata que los productos ensayados, confieren mayor elasticidad y resistencia al cabello. La peinabilidad tanto en seco como en húmedo mejora notablemente.Un conditionnateur est un agent chimique conférant aux cheveux nuis une certaine élasticité et une aptitude a la coiffure indépendamment d'un meilleur aspect (brillant, etc.) et d'une plus grande souplesse. L'efficacité objective de ce type de cosmétiques, quant aux propriétés tactiles, peut être vérifiée par dynamométrie. Dans ce travail, on détermine l'efficacité de quatre conditionnateurs commerciaux différents, en utilisant comme critere d'évaluation l'élasticité, et la charge a la rupture. On measure aussi l'aptitude a la coiffure en utilisant un dispositif spécial qui simule l'opération de coiffure dans le dynamometre. Dans l'ensemble, on constate que les produits essayés conferent une plus grande élasticité ainsi qu'une plus grande résistance aux cheveux. L'aptitude a la coiffure s'améliore notamment, a sec aussi bien qu'au mouillé.A hair conditioner is a chemical agent that confers to damaged hair some elasticity and combing ability, adding a befter look (sheen, soft, supple, etc). The objective eficiency of such type of cosmetics can be assessed by tensile testing. In this paper the eficiency of 4 comercial conditioners is evaluated by their elasticity and breaking load. The combing ability "combability" is also evaluated using a device adopted to tensile tester which simulates the combing operation. The 4 products tested show an improvement in hair elasticity, and resistance together with a better combability performance.Peer Reviewe

Huffman Coding with Letter Costs: A Linear-Time Approximation Scheme

We give a polynomial-time approximation scheme for the generalization of Huffman Coding in which codeword letters have non-uniform costs (as in Morse code, where the dash is twice as long as the dot). The algorithm computes a (1+epsilon)-approximate solution in time O(n + f(epsilon) log^3 n), where n is the input size

Synergistic disruption of external male sex organ development by a mixture of four antiandrogens

Reproduced with permission from Environmental Health Perspectives.Background: By disrupting the action of androgens during gestation, certain chemicals present in food, consumer products, and the environment can induce irreversible demasculinization and malformations of sex organs among male offspring. However, the consequences of simultaneous exposure to such chemicals are not well described, especially when they exert their actions by differing molecular mechanisms. Objectives: To fill this gap, we investigated the effects of mixtures of a widely used plasticizer, di(2-ethylhexyl) phthalate (DEHP); two fungicides present in food, vinclozolin and prochloraz; and a pharmaceutical, finasteride, on landmarks of male sexual development in the rat, including changes in anogenital distance (AGD), retained nipples, sex organ weights, and malformations of genitalia. These chemicals were chosen because they disrupt androgen action with differing mechanisms of action. Results: Strikingly, the effect of combined exposure to the selected chemicals on malformations of external sex organs was synergistic, and the observed responses were greater than would be predicted from the toxicities of the individual chemicals. In relation to other hallmarks of disrupted male sexual development, including changes in AGD, retained nipples, and sex organ weights, the combined effects were dose additive. When the four chemicals were combined at doses equal to no observed adverse effect levels estimated for nipple retention, significant reductions in AGD were observed in male offspring. Conclusions: Because unhindered androgen action is essential for human male development in fetal life, these findings are highly relevant to human risk assessment. Evaluations that ignore the possibility of combination effects may lead to considerable underestimations of risks associated with exposures to chemicals that disrupt male sexual differentiation.European Union and the Danish Environmental Protection Agency

Sliding mode control of switching converters: general theory in an integrated solution

The application of the sliding-mode control theory to the regulation of dc-to-dc switching converters is reviewed. Subsequently, linear dynamical models are derived and compensating networks are designed. An analog integrated circuit illustrating the theory has been designed, implemented and applied to regulate a buck converter in continuous conduction mode. Experimental verifications are provided.Peer ReviewedPostprint (published version